IOS app build

I"m reasking on this project, I need a membership based app that allow us to assign a mentee/client a mentor/consultant. I will need them to be able to communicate with FaceTime meetings and schedule meetings. I dont want to start from scracth because I need this in the next 72 hours on Apple store. it just needs to be clean and we can add to it or cancel functions your current app might have.