Locate and merge duplicate contacts
TIP: You can first export the contacts so that you have a backup https://help.infusionsoft.com/help/export-contacts-from-infusionsoft
The first step is to identify the duplicate records.
This article walks you through the process: https://help.infusionsoft.com/help/identify-duplicate-contact-records
After that is completed you would return to Admin > Data Clean up to merge.
Select one of these two options
When you merge duplicates the auto-merge will take information from the newer contact record and use it to update the information in the older (original) contact record, based on the records’ ID numbers.
Merge record will contain all of the tags, history, notes etc., from both records