Build Doctors Appointment Booking App

We want to develop mobile app to book or cancel appointments for our existing patients registered in our HIS (Hospital Management System) OR New Patients want to book appointment with Hospital.
Key Features of Appointment App Need to be Develop:
1. Appointments booked in App will be displayed in our HIS System.
2. Master data required for app will be fetched from HIS System.
3. Family Members Registration and Appointment.
4. Multi-level Authentication.
5. Patient Dashboard for displaying visiting history, prescriptions, discharge summary, lab reports through our HIS System or so on.
6. Video conferencing /Chat with Doctors Available.
7. Online Payment Gateway for taking appointment Fee.
8. Eye catchy and user-friendly design.
9. Cancelation of Existing Appointments.
10. Booked or Cancelled Slots or Free Slots of Doctors.

Points Need to be Concern:
Rest API Will be provided as per requirement through our IT Team.
Source Code is Mandatory.
Good Communication Skills and Support
App should be run on android and iOS Platform

This is initial and may change as per running requirements