My half marathon training plan had the wrong race day, and now I cannot train accordingly for the remainder of the month before my race.

Is there a way to re-open a previous running plan and change the race day to sync back up to where my training should be? My face date is March 17th (not February 17th) and I still have a few weeks to train. I tried to start a new training, but it will not let me select the proper date.