Can the Change Personal Information approval rule evaluate only the primary phone, email, address, or national identifier?

No. The rule evaluates based on the setting in the ORA_PER_PERSONAL_INFO_EVALUATE_PRIMARY profile option. The profile values are N, Y, and null. If you select N, the rule evaluates based on the record currently being modified. This is the default value.

If you select either Y or leave it null, the rule evaluates based on the primary record.