Blind transfer is a way to send your call directly to another number. You will not speak with the other party but only send the call. You can blind transfer your call to another extension within your phone system or any 10-digit USA/Canadian phone number.
When you are on a call, your in-call display will change to the image on the left:
If you wish to "Blind Transfer" a call, press the "transfer" button and dial the number where you wish to send the call. Once you click the blue "call" button, the call will be sent to the party you dialed, and the call will hang up.