Question
Is there anyway to remove a managed package (Action Plans) that was installed into a managed package dev (My Managed Package) org after being released? Assuming yes, are there any dangers or complications with doing this? Again assuming yes, once an installed org upgrades to the newer version of our managed package (My Managed Package) would we be able to remove the other managed package (Action Plans)?
Background
I'm working on a managed package that includes the Action Plans managed package module. We now need to customize Action Plans and to do this need to switch to the unmanaged version. We don't extend the package, just have buttons from it on some page layouts which we can remove. Seems like this may be possible, but could have some potential dangers. Since managed packages aren't so undo friendly and don't have sandboxes I'm hoping someone out there may have actually done this and be able to provide some real world info.