If you want to get a new union involved, first you would have to get Prospect derecognised (if such a word exists) - see my post of 30 March:
http://www.pprune.org/atc-issues/358...ml#post4826396 Then you would have to go through the reverse process to get another union recognised. This might be a tedious exercise without management cooperation - they might see divide and rule as a good option. Remember that in the interregnum, there won't be
any recognised union (for what that's worth).