We require two recommendations, one Academic Recommendation and one Character Recommendation. If you registered a recommender with the wrong recommendation type, you will need to exclude the incorrect entry and register your recommender again. To do this, click on your recommender's name on your Recommendations page, and then click "Exclude" at the bottom of the pop-up box. That entry will then become inactive, and you will be able to register your recommender again with the correct recommendation type. Your recommender will then receive a new link of the correct recommendation type.
You should also contact your recommender directly to explain the situation.