title: How do i use React Native to build a caller app without showing phone number?
body: <p>My client wants to allow his staff to contact his customers without showing his customer's phone number. </p>
  
  <p>I am thinking to build a caller app where my client and his staff both needs to download and install it on their phone.</p>
  
  <p>function on their apps:
  My client: he can save his customers' contact inside this app and the phone number will show on his side.
  My client's staff: He can make call using this app and the phone number will not show on his phone at anytime.</p>
  
  <p>I am able to make a phone call but how do i replace the default phone caller app inside their phone?  </p>