Allow Redaction in Merged Comment

Feature Request Summary: 

Allow users to redact portions of a comment placed on a ticket from one that was merged.

Description/Use Cases: 

Currently if there is text in a comment from a merged ticket included on a ticket, this text cannot be changed. The comment can be redacted on the original ticket at any time - even after closing, which is great, but this does not update the text on the ticket that it was merged into. 

Say there was a password on a ticket that needed to be redacted. The agent doesn't realize immediately that the text needed to be redacted and merges the ticket with another ticket that is about the same issue. The agent then notices the password and redacts it from the first ticket. This agent cannot go back to the remaining open ticket and redact the password or edit in any way.

Business impact of limitation or missing feature:

This issue is a serious security concern as agents can mistakenly add secure information to a ticket without a way to correct it.