RingCentral Phone - Desktop - Transfer Calls to Voicemail
To transfer a call to another number or extension, click Transfer, then enter the Extension number of another User in your account, or Phone number of the person where you wish to transfer the call. You can also click the Plus sign to select from your list of contacts.
NOTE: Call Transfers will swap the Initial Caller ID with the transferring party's Caller ID.
NOTE: When you click Transfer, your call will be placed on hold after you dial the receiving party's number or extension.
On the Transfer To window, click Send to Voicemail.
RingCentral Desktop app: Active Call Controls