Depends on when you bought them. I think that it is 7 days and you have to bring the receipt and the items in with you.
Funny story, I bought some underwear one day and the next it went on sale. The CM told me I needed to bring in the items and she would adjust them for me. I said I have them on, want to see! I gave her a laugh for the day and I got my adjustment.
Sharbear