I am not sure if this is what you are asking Refreshed. But, the usual rule for editing is that you can edit as long as there are no replies to your post yet but once there is a post under it you can no longer edit. The reason being sometimes people edit to the point that the meaning of what the original post said is changed to the point that the rest of the thread doesn't make sense anymore as the reply was to the original post, not the edited version.