I did following (I simplified this comparing to a reality):
- created a branch Branch1, switched to it
- added file File1 and modified existing file File2 and commited this
- figured out that I don't need File1, removed it and commited this
So, the actual difference between original branch and Branch1 is only modification of File2.
I want to get this actual difference between branches and put in Branch2. Generally speaking, I want to get rid of not necessary history of adding/removing File1.