EW, it's called a debate.
The debate will end with one motion, or the other, being voted in; either the Union is to 'consider members within NATS as a single workforce and to resist any attempts to differentiate between the terms and conditions of those within NSL and NERL' or it is to 'consider differing National Agreements, including pay and working practices, for NSL and NERL if this is in the best interest of the members'
(My bolding).
It's either one or the other, surely. There is no 3rd option.