Thread:Old McDonald/@comment-26306690-20160224014602/@comment-24494906-20160226153050

? Only admins/discussion mods can delete comments. They can also edit the comments.

People can edit their own comment, and nothing can keep them from doing that. However, I think you can take a look at what they changed by clicking "History" on the comment. Or if that doesn't work, by looking up the edit under Special:Contributions/Special:WikiActivity/Special:RecentChanges.