If it's shows already set, you can go to series manager. Menu - Recordings - Manage Recordings - series manager. Here you change priority, settings, and remove. If this doesn't answer the question, let me know and I'll help further.
if your talking about recordings you have already scheduled, go to Manage Recordings, and you can change to first run or re-run or both. you can also schedule to record early. IF this is not the information you are asking let me know more in detail and I'll be happy to assist.