To me, this seems to depend on the agent. I've had some be flexible and some not so much. I actually had one agent make me call back (called prior to midnight with bunch of other business to take care of) and when I reached the end of the call it was 11:55 PM and asked to upgrade within the 7 day window. She insisted I call back in 5 minutes, stating the "system" wouldn't allow her to do it.