In these final days, the most common phrase spoken by retail employees everywhere is...
"No, we don't have that." Or its cousin, "No, we're out of stock."
Make sure in tomorrow morning's huddle that you remind you staff that there is a better response...
"Let me show you what I do have."
Learn to say that instead.
Before you say no, lead the customer over to an alternative. Put the alternative in his hand. He doesn't want to drive all over in these last couple days for something that might be hard to find. More often than not he will accept the alternative.
But only if you offer it!
PS This works well in January, too. In fact, you should always use this approach. Positive beats negative in the retail game.