Panasonic KX-TVM50 Programming Manual page 49

Forwarding Mode
Specifies if forwarded messages are to be retained in the original mailbox. When set to "Copy", copies
of the messages are retained in the original mailbox after forwarding. When set to "Move", messages
are forwarded to the receiving mailbox and are not retained in the original mailbox.
Value Range
Copy, Move
Feature Guide References
2.3.2 Auto Forwarding
2.1 Mailbox Settings
Programming Guide 49