How do I apply a single "change"

Forgive me for the _incredibly stupid questions_,
but how do I apply a single "change", identified
by its SHA?  Either from one branch to the other or
remote?

I.e. I want to "integrate" only that change?

Alternatively, how do I apply the absolute output of
"git-format-patch".  I tried but whatever I tried with
complained that it couldn't find any email addressess.
(roll eyes here)

Thanks for the help,
   Luben