You can use amend within VS.
Change what you want to change and in the
Team Explorer - Changes window click
Amend Previous Commit.
This will change the last commit and rewrites it with your changes (amend).
On the CLI, this would look like the following:
git commit --amend (with options to change the message too)
The documentation is pretty good on that topic:
CLICK HERE to find out more related problems solutions.