Frankly the trailer gives a bit too much away, but still ... Zoey Deutch (Lea Thompson's daughter) is Executive Producer and also stars as Rachel Meyer. She co-owns a bakery in New York City and has a boyfriend. One evening leading up to Christmas he is shopping at Tiffany's for an appropriate gift, he selects some nice but "affordable" earrings. He leaves the store with the gift in a nice blue Tiffany's bag.
At the same time a man visiting from Los Angeles, a professor and author, is picking out a nice, expensive ring for his girlfriend flying in, his plan is to propose on Christmas Eve. He and his young daughter leave the store with his gift also in a nice blue Tiffany's bag.
The first man gets hit by a cab, the second man sees it and rushes to his aid, both blue bags end up on the street surface near each other. They inadvertently get switched.
So this chance meeting and switching of bags sets all kinds of things in motion, causes lots of confusion, as the four principal characters and their friends and families work to understand what all happened and to sort it out. In the end, as nice pleasant movies always do, things work out for the best for all in the end.
My wife and I watched it at home, streaming on Amazon Prime. Nothing much novel, just pleasant entertainment.