Moving a branch to a different node

Hey git users,
    I am working on a project where I proceeded by the following steps:

starting from master...
1) create branch foo
2) work in foo, make some commits, then a patch named Foo
3) create a branch bar while in foo
4) work in bar, make some commits, then a patch named Bar

git show-branch gives me

! [master] Hello
 * [foo] Foo
  ! [bar] Bar

I would like to make bar split off of master instead of foo so that I can
format a patch that can be applied to master (Bar) without having to first
apply Foo.  Is there a way to do that?

Thank you!
~Mike