Hmmm... Maybe we should back up and discuss the overall goal. What needs to be done?
It sounds like the President wants his calls screened by the Assistant and not to ring at his desk.
Does this need to be permanent?
If that's the case then I would suggest setting Bridged-appearances on the Assistant's station and setting the President's phone to a delayed or no ring.
On the President's phone
Set Per Button Ring Control to "y" on Page 2
Set call-appearances on page 4 to
Auto-A/D: Y
Rg: (d)elay
On the Assistance's phone:
Add bridged-appearances to free buttons:
brdg-appr b: 1 E: XXXXX R:r Set one per call-appearance (1, 2 and 3)
B = The button number to "copy". Buttons 1, 2, and 3 are typically the call-appearances on a phone
E = The Extension to "copy", in this case, the President's extension
R = The Ring type. r for immediate ring
I would also recommend setting
Auto Select Any Idle Appearance to "y" on the Assistant's phone to allow the Assistant to transfer a bridged call via his/her own call-appearance.
The Assistant now has the President's phone number on her phone in addition to his/her own. Incoming calls will be visible on the President's phone but will not ring immediately (if delayed). Call will ring immediately on the Assistant's phone.
The default value for the delay is 2 rings but can be changed under system-parameters features, page 1
Auto Abbreviated/Delayed Transition Interval (rings) if the Assistant needs more time to answer a call. When transferring back, the call needs to ring at least 2 times before the President's phone will audibly ring.
You may need to adjust the coverage path, depending on the number of rings.... So if you change the delay to 3 rings then make sure the President's coverage path uses at least 4 rings before going to voicemail.
If you really want to get fancy, set up a second station for the president in a range that is not typically used and does not have a DID associated. the station does not need to be logged into a phone. Assign bridged-appearances of this to the President's phone. With the above setup, calls to the President's PUBLISHED number first ring to the Assistant. The Assistant then transfers appropriate calls to the President's UNPUBLISHED extension. When the President places an outbound call, he will use the PUBLISHED station call-appearances. Only the Assistant needs to know the super-secret extension.