Yes; it depends on where the call originates.

If the caller originates in Unity, you can specify different transfer rules depending on the subscriber or call handler schedule (open, closed, holiday, etc).

If the caller is being handled by just UC Manager, then you can use schedule-based routing; however, this does not typically scale down to a single phone well. This is used when you want to change routing behavior in mass scale.

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/7_1_2/ccmsys/a03tod.html