As stated above, I believe there is a form you fill out. As long as you can hold the floating week, it's yours.

Concerning reserve and using a floater: be careful. The company can slide the FV week to only drop one trip. That's one of the many reasons floaters are almost always a bad deal except in very specific circumstances.

Floaters have their place, but don't let somebody talk you into thinking they are a substitute for real vacation weeks. I have flown with somebody who swore by them because he couldn't hold the weeks he wanted. I tried to sell him on the program of trading and selective sick calls that 99 percent of us have adopted, but he wouldn't hear it.