If I bail someone out of jail can I get the money back at any time?

The money is the fee you have paid to get the person out of jail.

Once that person walks out of the jail, the money belongs to the bail agent. If you signed to get someone out of jail and you no longer want to be on that person's bond, you need to tell the bondsman you want the person returned to jail. When the person is back in jail, then you are relieved of any financial liability.