Finalizing is just a way to say that you are amenable to orders being processed before the deadline.
If all players who are required to enter orders for a phase finalize, then the system will process all the orders immediately.
But if just one player does not finalize then the system waits until the deadline to process.
It's just a way to speed up the game, particularly towards the end of a game or in retreat phases.
Either way as long as you have entered any order, you will not NMR.
Do not feel under any obligation to finalize. Especially if you are in the middle of negotiations with someone,
which you should almost always be