adding bookings to sqlite after admin comfirmation

I am trying to develop an android booking application. I am going to use sqlite to keep bookings. I don't have trouble with adding bookings to database, but my actual wish is that when a user maked a book, an admin account should preview it to analyze the availability of that booking before it added to database or the admin can take an email to confirm availability of booking.

Right now I stucked at this point and I have no idea how to solve it. Please help