Sorry for the delay. This is the article with instructions on how to sync existing Mission Plans to Map Pilot Pro.
But... Since there is no longer access to the app that contained the missions and they are not already synced to Maps Made Easy there is no way to access them. The older versions of Map Pilot were all announced to have been end-of-lifed at the end of 2020. It was still functional for all of 2021 which gave plenty of time to transition over. As noted in the app popups and emails that were sent out any syncing or data access functions were going to be ended by the end of the year 2021.
Text from the email:
Your current copy of the app will continue to work but we can't guarantee all features will continue to function properly beyond May 15, 2021. Anything related to elevation/tile services, flight log syncing, mission syncing, and automated mission naming will cease to function at some point. As long as you are not using any of those features the basic functions should continue to operate until the end of the year.
The best way to recover any mission that you have already flown but not synced to Maps Made Easy would be to export the KML from the flight's detail page and import that into Map Pilot Pro which should give a good guideline to use to duplicate what has been done previously.