This is a bit of a hack and may not even be exactly what you are looking for, but you could export the log as JSON, do your thing, and import the log back. This is not particularly neat or user-friendly, but should work as long you use a
real text editor (and not for example Word) and don't touch the ID fields containing gibberish. And make a back up copy first.
A more elegant way would be creating the malleable detail as a separate log entry and using tagging to link it to wherever it is needed. Whether this is practical depends on your use case.