Looking for the tile of a '50's Grace Kelly movie... she worked in a New York (or some other big city) office... they were preparing for the office Christmas party and there was a large decorated Christmas tree in most of the scenes in the office... Really want to find out the name of this movie. Thanks.

Did you check CBS's TV series... DANGER... she was a character on there. Ran for I think 5 seasons. Could it be that one of those episodes is the 'movie' you are thinking about??
Suggestion.