Yes of course it's NOT possible to change names by users. Just try to imagine hundreds of active before people/forum users starting to change their nick every week and posting things. Confusion is the best what it would cause. No sense in that.
Anyway let me know what you want me to chang your nick to - your new name ? - and I will change it for you (unless it's already taken)... So let me know. But it shouldn't be done very often. Let's make an exception for you.
Of course you can remove profile and make a new one - but that will also cause a problem because your old posts will be with your old nick and new with new one. It doesn't make any sense in terms of order and identification.
So it's better to let me change your old to new one. Just post it and will be done for you.
See you later.