Its an if bet on a pending play.
If you bet your whole $500 balance on a game thats at the half, and there is another game thats starts in 10 mins, but your your whole balance is tied up on a game that does not end for 2 hours, you can call the book and tell them you want to bet on the game that starts in 10mins with money on the game thats at the half.
You can bet anything on this new game up to $1050 bucks with the example I used above with the $500 bet.
If the game at halftime loses, you automatically have the second game cancelled.
