Can I help you?
Yes, well, I bought this tie last week for my husband's birthday, and er...well he doesn't like it. Could I change it for something else, such as a shirt or a hat?
Certainly, madam, provided that it hasn't been worn, and if you have the receipt.
Yes, here it is.
OK, er... this tie looks as if it were worn. I'm afraid I can't put that back on the shelf.
Oh, that's a pity.