Upvote:1
If you want to return as a visitor to the US after Aug 15th and for just a month, there's two things you can do:
1- File an I-539 form to change to a B1/B2 status*
2- Go across the border to Canada and re-enter the US under the VWP which you're entitled to as a UK citizen
* Note that you're still out of status even if you have timely applied for a change. Since you have to mail the application, that could be slower than the second option