Try each of the following steps in order until the issue is resolved:
- Download and run the Duplicate Phone Types plug-in to identify constituents that might result in duplicate phone types if one phone type is replaced with another. Manually correct the records the plug-in identifies
- Check the following record types for the phone type that could be considered a duplicate if one phone type is replaced with another: nonconstituent relationships, participants, action tracks, and financial institutions. Manually correct these records.