What do you mean by "How will it work when we log in"? if its after the merge, there will be maintanance while they are transfering characters to the new server, after that we will login to our new servers, even those who transfered.

And there is no way to revoke an application, SE has numbers for each server, if you chose to transfer to another server when you selected to move you gave your spot on the server to the next person that transfers to your default merged server.

They have done this to keep them balanced, so we don't get people rushing to one server leaving the others dead.