[p4] Fixing a Branch to Reflect an Earlier Release

[Vander Werf, Bruce]

We have a situation here where a release branch was created based on the
latest revision in the main codeline, but it should have been created on
an earlier revision. How can I repair this so that the release branch
reflects the correct revision? 
 
I tried integrating that revision from the main branch to the release
branch, but it reported that the revision had already been integrated. 
 
Can I use obliterate to just destroy the branched revision and
re-integrate?
 
-Bruce