Update person table user records based on unique attribute

Dear Experts,

OneIM Version 8.2

(contractor to fulltime employee use case)

We have an HRMS system and we are onboarding User records(Contractors and FullTime Employees) from HRMS to OneIM Person Table.
E,g. FirstName, LastName, EmployeeNumber(PersonnelNumber), ID, etc.

EmployeeNumber and ID are unique for every User.

Scenario:

User exists in HRMS and Person Table. HR creates a new entry with the same user name in HRMS, aggregation task runs and if the ID's value of the new entry(User) already exists(matches with entry) in OneIM Person Table(EmployeeNumber will be different), it means this new entry is the same User which is already exist in OneIM Person Table and HRMS. In this case, we don't have to insert the User as a new User in OneIM person table. We just want to update the existing User record which is in OneIM Person Table. Only EmployeeNumber(PersonnelNumber) should be changed for that user. All the values(CentralName and EmailAddress) should be the same.

We just have to trigger an update operation if an ID value is matched to an existing User. Could anyone please suggest if is there any processes/scripts where I need to make some changes or if is there any approach?

Your quick response would be really appreciated.

Thanks in advance.