It is about a family where their farther has died any they are invited to his house and it is Christmas time. There is one girl and 1 boy also they come with a lady I don't know if they are related to her or she just cares for them also the place that they are invited to stay over at it is their uncles. The house is a mansion.

Also it is s kids movie

Thanks,
Xxxx

My first thought is this:
The Amazing Mr. Blunden (1972)
IMDb synopsis:
Mr. Blunden, a mysterious, elderly solicitor, visits Mrs. Allen and her two young children in their tiny Camden Town flat and makes her a wonderful offer. The family become the housekeepers to a derelict country mansion in the solicitor's charge. One day, the children meet the spirits of two other children who died in the mansion nearly 100 years ago. The children prepare a magic potion that allows them to travel backwards in time to the era of the "ghost" children. Will the Allens be able to help their new friends, and what will happen to them if they do? Can they change history?