Hi Lester,
If this is just a one-up type of setup you can configure a Voicemail profile (in CCM) for ext. 0285 and apply it to ext.0216 that will allow this type of Call Forward to 0285's mailbox.
Or in Unity set up Alternate Extensions so that 0216 is an Alternate Extension for User 0285. Sharing a Cisco Unity Voice Mail Box between Two or More IP Phones
Configure Alternate Extensions
Open the Unity System Administrator web page.
Navigate to the subscriber's profile. Select Subscribers > Find and Select a Subscriber > Enter Subscriber Information then click Find and click the Subscriber's name for the subscriber that owns the primary phone (Phone B).
When the subscriber page comes up, select the Alternate Extensions option and click Add.
Enter the alternate extension number (in this case Phone A) and click the Save icon.
From this good Unity doc;
http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_configuration_example09186a008015ceec.shtml#steps
Hope this helps!
Rob
