When you do a Blind Transfer, then this is done without actually initiating a call to the other extension. The call is transferred blind. Compared with Attended transfer, you setup an call with the other extension and this person can decide to accept the call or not. When the other side accepts the call, the call on-hold is transferred. You also have the option unattended transfer where you setup the call to the other extension and before they answered, you already transferred the call on-hold. For the End-user, unattended and Blind transfer acts the same. The differences are more on the protocol level.
Does the N720 support Blind transfer?
The N720 does support Attended, unattended but not the Blind transfer feature.