Originally Posted by
wheatbeer
As soon as your online account shows Platinum you can enroll for Hilton Gold via the Platinum Benefits webpage. From then the time it takes varies could be a few days to a couple of weeks.
US Platinum cardholder here... and can report that I've been waiting 2.5 weeks so far. Took almost two weeks for Amex to process the enrollment (not sure why it took that long, it seems like they are usually processed a lot quicker) and am now waiting for Hilton to process the data received from Amex to upgrade the account.