It is correct that when you change your W/L from 31 days out to 7 days out it simply extends your W/L. It does NOT change your "place" in line unless you cancelled that W/L first. I've done it many, many times. Both online and via MS. When I KNOW I want what I'm wait listed for, like when I have an alternate rez that is set up to be cancelled if the W/L comes through (LOVE that feature!), I will just set it up to last until 7 days pre checkin right from when I get on the W/L. Once you are 7 days out the only thing you can do is keep checking inventory either online or by calling.