Premium RaidPass is one time use only.
I will not even say how sad it is for me.
What did you expect for 100 coins?
It's one use per specific raid but if you don't beat the boss & are there for the full length of the raid it can be re-used until you beat the boss or until the raid timer expires.Had to reuse one today 4 times to beat a lvl 3 Alakazam because there were only two of us.
Just make sure you join the Raid with enough time left on the clock to re-enter and try again. Otherwise, it's a waste of a pass.