For some, it's the red reindeer Christmas sweater. For others, it's the diamond-encrusted dreidel. Whatever your worst gift nightmare might be, Amazon may soon give you a reason to cheer.

The online retail behemoth that's the source of many presents — may they be good, bad or ugly — has patented a system that would let people exchange unwanted gifts for those they actually want. They could do this before they actually receive the gift.

Seattle-based Amazon.com Inc. recently patented a "system and method for converting gifts" on its website. It took nearly five years; the company had applied in March 2006.

For now, though, it's just a patent. So until Amazon figures out how to implement it, you may be stuck with that itchy sweater.