Overview
In Passport, a duplicate member record is created when a new member is added that exactly matches an existing member record in the database on all three key fields: First Name, Family Name, and Date of Birth.
If an administrator creates a new record for a member who has previously registered with a different club or association, the Passport database will identify this and allow the administrator to merge the member's new record with all of their historical data through the Duplicate Resolution feature.
Step-by-Step
Step 1: Navigate to the Duplicate Resolution screen
From an Association database, open the Members menu and select DUPLICATE RESOLUTION

Step 2: Review Possible Duplicates
The Duplicate Resolution screen will appear, showing any possible duplicates recognized in your database. The member data is shown in two columns:
The Problem Record: The left column, which is the newly created member record that caused the duplication.
The Suggested Match: The right column, which is the existing member record that was already in the database.
Other member data like contact details, association, club, active status, and member number are also shown to help you decide which member data to use

Step 3: Resolve the Duplicate
On the right side, under Choose option, select one of the following five options for each possible duplicate:
This is the same person (Merge using new data as the base): Select this option if the new record is the same person and contains more up-to-date contact information. It uses all new member data unless a field is blank, in which case it uses the existing data
This is the same person (keep existing data): Select this option if the new record is the same person, but the existing record contains more up-to-date contact information. This option will retain all of the member's existing information
This is a new person: Select this option if the new record, despite having the same three matching fields, is in fact a different person
Oops, delete this person: Select this option if the new record was added by mistake and you wish to delete the new record. This action will not affect the member's existing record
Ignore this person for now: Select this option to defer a decision on resolving the duplicate until a later time.

After selecting the appropriate resolution option for each possible duplicate, click the UPDATE DUPLICATES button
