Merging External candidate to Internal employee who is active in the system

Summary: If an employee applies via career site with different NID and we move the new candidate profile to HR, how should we merge the candidate profile (external) with the existing employee record in the system?

Content (please ensure you mask any confidential information): We can cancel the work relationship for the new record but how do we move forward for merging since the duplicate doesn't work with employee records. What should be our solution for this?

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