Steward to a monk/monastery

Perhaps, this is what you're looking for. Please see the bolded text for something that you say to a Bhikkhu to help him, in the case that you're not a steward but just a layperson interested in donating.

From the footnotes of the "The Bhikkhus' Rules: A Guide for Laypeople" by Bhikkhu Ariyesako:

Footnote 105:

"The Buddha had to steer a middle course between honoring the laity's generosity and concern for the welfare of the Bhikkhu-Sangha and preventing the bhikkhus from receiving and using money. Thus, while bhikkhus are not allowed to receive money for their use, they are allowed to accept things obtained from a properly-deposited fund. This is usually done through the services of a monastery-steward who is entrusted with money provided by lay people. In our modern, money-dominated world this may appear as a subtle and refined point, however, it may be helpful to compare this arrangement to a special Trust Fund from which the beneficiaries (in this case, bhikkhus) can only receive material requisites. That is, the donor (temporarily) establishes a Trust Fund to provide a bhikkhu with requisites through the monastery-steward as manager." (HS ch.14)

"...the Buddha permitted money to be entrusted by a donor to a steward, who may be a monastery attendant or a lay follower, for the personal benefit of an individual bhikkhu, thus:

'There are, bhikkhus, people of faith and confidence (in the Sangha) who entrust money into the hands of monastery stewards saying, "With this, provide the bhikkhu so-and-so with what is allowable." I permit you, bhikkhus, to accept an allowable item obtained thereby. But this, bhikkhus, I do not say: that in any circumstances may gold, silver or money be accepted (by a bhikkhu, or) be looked about for (by him).'

"When the donors ask the bhikkhu, 'Has the Venerable One a steward?' or, 'Is there an appropriate place where I may deposit this money,' or some similar question, then the bhikkhu may point out a suitable steward, or he may indicate an appropriate place. Should the donor deposit the money with that steward, or in that place, then it is properly deposited." (AB)

Footnote 106:

"Money given to a steward of the Sangha (veyyaavaccakara), for the use of bhikkhus or to stewards of individual bhikkhus, is not given to the bhikkhus for them to possess. The steward holds the money of the donors in trust, and should a bhikkhu have legitimate reason to make use of this (travel for Dhamma, Requisites, Dhamma-books, etc.), he can request the steward to supply him with the article needed. He cannot purchase it himself. "This rule concerns money of which a bhikkhu has such thoughts as, 'It is mine' or 'It belongs to me' and which he intends to use for purposes other than those of Dhamma." (Paat. 1966 Ed.; p104-105)

Footnote 107:

"The Monastery-Steward: The monastery-steward is usually someone who is a close supporter of the monastery. Not only should he/she ideally be well-informed about the monastic guidelines relating to money, but also be knowledgeable about what is appropriate to provide and the proper procedures for doing so.

"When a fund has been properly established and the bhikkhu is in need of a requisite, he may approach that steward and state what he is in need of. Should a bhikkhu command the steward to: 'Buy me this,' it is considered a case of dubbhicaritata (wrong procedure) and that bhikkhu may not make use of any article obtained therefrom, although other bhikkhus may use it.

"It is a fault of Acknowledgement with Forfeiture [Nis. Paac.10] for a bhikkhu who receives a requisite by badgering the steward beyond verbally reminding him three times and standing silently up to six times. If the required requisite is not forthcoming the bhikkhu is obliged to inform the donor that the invitation to requisites has not been fulfilled. The Commentary says that if the bhikkhu does not inform the donor it is a fault of Wrong- Doing "for breaking a custom"). The donor may then take up the matter with the steward." (HS ch.14)

"A bhikkhu may not command (tell) either the donor or the steward what to do with regard to the gift of gold or money. However, he may give them hints, or suggestions, or any information, as long as these fall short of ordering the donor or steward. Also, a bhikkhu may not accept the ownership of gold or money offered to him indirectly, for example should a donor say to him, "In such and such a place is a certain amount of money, I give it to you." then the bhikkhu is obliged to reject the gift by words or by a gesture of refusal or by mental resolve (e.g., determining, "I do not accept this") otherwise he incurs [an offence of Confession with Forfeiture]." (AB)

I believe that you are looking for the term Pavarana.

Here is a description from The Bhikkhus' Rules: A guide for Laypeople:

Normally a bhikkhu will not ask for things. Instead, he will wait for something to be offered. This is exemplified in the alms round where the bhikkhu makes no request, does not even look at people, although he may quietly wait to see if an offering is to be made before moving on. One way that lay people enable a bhikkhu to ask them for help is by making an invitation or pavarana.

The Buddha allowed a bhikkhu to accept pavarana or 'invitation.' Such an invitation is made when lay people decide to commit themselves to supplying medicines if a particular bhikkhu should ever become ill, or it can be a broader offer of help. (Although a sick monk is allowed to ask anyone for medicine, asking somebody who has already invited him with a pavarana invitation is obviously preferable.) Therefore if lay people meet a bhikkhu who seems worthy of help and support, they may make such an invitation. Quite a number of the rules deal with what and how much may be asked for when a donor makes this formal invitation.

An invitation can therefore be quite specific about what is being offered and how long that invitation will last. (Obviously, if circumstances change or the request is unreasonable, the donor has no obligations — and a conscientious bhikkhu is always sensitive about this.)

A clear invitation will also help prevent misunderstandings. For instance, the bhikkhu will know exactly what has been offered and so will not ask for more than that; and the lay person will not be overwhelmed by extravagant requests.

The original circumstances of the forty-seventh Confession Offence were as follows:

A lay supporter possessed much 'medicinal ghee' so he invited the monks to make use of it during the following four months. Much of the medicine was still left, so he extended his invitation for another four months and then extended it for life. The Buddha allowed this. However, that same lay donor had once criticized the 'group-of-six' monks because of their previous improper conduct so they decided to take their revenge by asking him for an impossibly large amount of medicine (ghee) and then criticized him when he could not immediately produce what he had promised. This rule was set down:

"A bhikkhu who is not ill may accept (make use of) a four- month invitation [pavarana] to ask for requisites. If he should accept (make use of) it for longer than that — unless the invitation is renewed or is permanent — it is [an offence of Confession.]" (Paac. 47; BMC p.393) When the invitation is more vague — for example, a lay person may just say, "If you need anything, Bhante, let me know" — the bhikkhu should not exceed the spirit of the invitation. In fact some communities consider that an invitation in which the lay person does not mention any time limit is valid only for four months and that taking up the invitation beyond that time is an offence.

A bhikkhu is always allowed to ask for requisites from his relatives without having formal invitation first. (Whether they actually supply anything is, of course, up to them.) 'Relatives' are considered to be those with whom the bhikkhu has common ancestors back through seven generations, on both the mother's and father's side. Here 'in-laws' are not counted as relatives.

"Thus all descendants of one's great-great-great-great-great- great-great-grandfather are counted as one's relatives... [although] a bhikkhu at present would be well-advised to regard as his relatives only those blood-relations with whom ties of kinship are actually felt." (BMC p.183)