How do you rename a thread. I need to add a 'Solved' tag since one of my songs was identified. I changed the title on the first post but apparently that was just a first post title and not the actual thread title.

Lyrical

Interestingly, the automatic search function found a thread that answered my question. I guess I need to make a request to a moderator/admin. The first post title was changed to 'Help with 3 songs plz(#3 solved)'. Can you rename the thread to that plz?

You're searching for 3 songs but only found one, so renaming your thread won't help in finding the other 2.
I've done it since you want it though...