You need to modify the Ringlist.xml file and DistinctiveRinglist.xml file with the rings you want to be displayed on the phones. Upload the ringlist files onto all CallManagers (Pub - Subs) in the cluster along with any new ringtones. Then you need to restart the tftp service on all servers in the cluster. If you modified a ringlist and you dont see the changes on a phone then maybe you didnt put the ringlist on a CallManager that the phones are registering to or the service needs to be restarted. Hope that helps.