Upvote:2
If it was annotated in the visa page then I am afraid you will be questioned upon arrival, the annotations in the visa are actually there for that purpose.
Anyway, you still can try a few things:
Get a letter from the training center stating that the training which was suppose to be held on Miami was moved to a new location, present this paper to the officer upon arrival and things should go fine;
You can try to land at Miami as annotated, then find a way to go to the new training place.
Talk to the embassy and figure it out officially.