This should help :-
<a href=”http://publib.boulder.ibm.com/infocenter/systems/scope/i5os/index.jsp?topic=/rzam8/rzam8fixremove1.htm&tocNode=int_215210″>Removing software fixes</a>
It is usually impossible to back out cume PTF packages. This is because there are almost always PTFs in the cume package that require Permanent application.
To back out a cume PTF package, restore your operating system and Licensed Program Products from backups made before the cume package was applied.
I’ve never heard of anyone backing out a cume package. I have, however, heard of individual PTFs from the package being backed out.