How do you edit a mistake in a title?

That's my question

 

I dont think you can, if I remember rightly.

 

Do this if it's a thread you started :-
At the top right of the page, above the first comment, you will see 'Thread Tools'
Click on that and you'll see a drop down menu.
In the menu click 'Edit Title' and you'll be able to change it.

 

Thanks @wiseowl . Not an egregious error - but who knows what might happen in the future