You can set up call forwarding for your Cisco IP Phone through the Cisco Self Care Portal with the Call forwarding options.
You can't set a schedule via call forwarding but you CAN set a schedule if you are associated to your extension # via your Directory ID and you use Single Number Reach.
NOTE: If you are accessing the Cisco Self Care Portal from off campus, you will first need to connect to VPN.
Learn more about call forwarding and the Self Care Portal at Cisco Product Support.
For detailed instructions on transferring calls using Cisco IP phones, you can refer to the Transfer Calls on a Cisco IP Phone 6800, 7800, or 8800 Series article on Cisco's site.
Information courtesy of Cisco.