Skype won't let me edit/delete other people's messages

Skype won't let me edit/delete other people's messages

In an old version (5.x, I don't remember the exact version) of skype, I
was able to right click someone else's IM and have the option to modify or
edit it, like I can do to my own IMs:

However, now I can only see this when I right-click someone else's IM:

I created the group and my role is CREATOR (that's what it said after I
did /get role)