It is up to the authors (all authors!) of the code to change existing licenses. You cannot just change a license
I WAS TALKING ABOUT MAKING SURE THAT:
1. If all licenses in .pas/other files say "modified LGPL"
2. then the lpk file matches those licenses
3. if the author indeed intended to publish under modified LGPL
Once again, I cannot know what license the author intended, but it is not possible to have a package/project with a "modified LGPL" license if any license in any part of the code does not allow "modified LPGL". This is the case for GPL, "normal" LGPL licenses etc.
In short/the easy solution: make sure the authors agree and that the licenses in all parts of the code match.