./installFixPak -a

I am unable to find any information on how to uninstall a fixpak on db2 if you originally install the fixpak (fp11 in this case) with the
>./installFixPak –a command. I know the -a means "apply", not "commit", but

--how does one uninstall if the FixPak install goes bad?

-- How does one later "commit" the install?

-- Can a database still be used as normal if the fixpak is only applied, versus committed? Rather, can you give the database a "test run" to see if the fixpak has fixed what you wanted it to without committing?

I can't find the anything about this on the internet. Can someone please direct me to a resource for this information on the internet? IBM's website does not go into detail about installfixpak -a. Any, and all, help would be appreciated.

Thanks for your time and help in advance.