Add to or change title of Topic

Hi how do i change or add to a titlle of an original thread, eg New photos added ,or update on....., so that people know its got new stuff added, and dont ignore thinking its an old post. Thankyou

Not sure if you got an answer to this or not, you will need to ask one of the Mods to do it for you as you won't be able to edit the title yourself unless its not long been posted.