I'm trying to locate the title of the following movie, and perhaps the stars.

It takes place in Manhattan (NYC).

Events around the XMAS/New Year's holidays.

A "light" comedy, perhaps some romance surround her older sister.

It was filmed post WW II (I think.)

It featured a preadolescent girl. She lives in an upscale apartment with her family. She gets into all kinds of mischief.

Any ideas?

Thanks !

Here's one possibility:

Tenth Avenue Angel (1948)
starring Margaret O'Brien, Angela Lansbury, George Murphy
IMDb synopsis:
Flavia's been told that her Aunt Susan's fiancé, Steve, has been on a trip around the world, but in truth he's finished his prison term. Steve wonders how he can make some money and is approached by his old associates. When Flavia discovers the truth about Steve, she loses all faith in her family and in God, and it will take a miracle to restore Flavia's belief and Steve out of trouble.

Tenth Avenue Angel (1948) - IMDb (http://www.imdb.com/title/tt0040865/)