IVR - After hours pin number

Hi,
I’m working today. At work I don’t get cell phone reception.
When a user dials in they get the IVR and call select an extension.
After hours my extension doesn’t ring it automatically goes to the answerphone.
Is there away to have someone push a pin number after they dial that extension to get the phone to ring and then if not answered have it divert to answer phone?
Thanks