Do I Need a thread editing/moved?

[GAB]

I have a gun for swaps only listed here:
http://forums.zeroin.co.uk/showthrea...sories-for-GBB

I am now in a position where is be happy to sell the gun, but still up for a swap.

I know I shouldn't relist it so what's the procedure? Do I just put a comment on the existing thread or can I get it edited and moved?