I got married 6 months after starting. I made the CP aware of the situation well in advance, and he was sympathetic. He said do the best you can in bidding, and if not, he would approve an unpaid leave for it. I got a composite line and crew scheduling created my line with a lot of time off around the event. Just communicate and they'll be reasonable. But don't expect the whole month off. Just like everything, it's a negotiation.