When you transfer a call to another person, you have the option to talk to the person before the transfer completes. If your phone supports a blind transfer, you can automatically transfer a call without talking to the other person. The call is automatically transferred after you dial the number you’re transferring the call to. 

To transfer a call: 

1. From Active Call, Lines, or Calls view, tap Transfer. The active call is held. 
2. From the Dialer, place a call to the person you want to transfer the call to.  
3. When you hear the ring-back sound, tap Transfer to complete the transfer. Or, if you want to talk with the person before the transfer completes, connect and talk with the person, and then tap Transfer. To cancel the transfer before the call connects, tap Cancel

To perform a blind transfer: 

1. From Active Call, Lines, or Calls view, tap Transfer. The active call is held. 
2. From the Dialer, tap Blind, and place a call to the person you want to transfer the call to. If you don’t see Blind, tap More (at the top of the screen), and tap Blind.
The call automatically transfers to the person you specified.