Well for starters they have to make sure the government will grant you
a visa, that has to pass first.
You also have to declare that you will fully quit your present job and
give up your senority number there and provide a letter of full resignation
from your airline.
It's not a trick if thats what you are worried about, just making sure
there is nothing to get trapped by before you leave your current job.
It appears you are in the pool, congratulations.