Change database of Live App without Data Lose

I want to update the database of my existing app(for new version) which is live on the app store. So I need to delete my existing database before using app or I can change the name of the database. After it If data exists in my old database I have to get all data and insert it again to my new sqlite file.

It looks like a slow process. My users don't want to loose data. Is there any other way from which I can easily change database of my Existing App without any data lose.