Microsoft hiring event, joining date.

Hello all, I recently got an offer from MSFT atlanta, and wanted to know if anyone is aware of the joining date yet. I should be done with the background check in the next two days. I am in a unique situation where my current employer has already filed for my stem opt extension and I would like to delay ny msft joining date until I get my ead card. Is it possible to delay the date.? If so, how should I go about it. Thanks. #microsoft #stem #opt #msft