Hello ,
welcome to the Polycom Community.
The community's VoIP FAQ contains this post here:
Oct 25, 2011 Question: How can I change my Ringtone or Ring in a special manner for a certain incoming call?
Resolution: Please check => here <=
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Best Regards
Steffen Baier
Polycom Global Services