This is actually against the rules. If you enter the hunt and answer “present” at roll call, you should only miss your run for a serious reason (like a broken leg, or a heart attack). If your travel plans require that you leave before the end of the trial day, you should consider whether or not to enter the hunt. If you do have to leave before your run time, you need to tell the hunt chairperson and secretary ASAP. (It matters because the absence of your dog may create a problem for how the rest of that pack is judged.)