You may find that you have a customer signed up for the program twice, with different email addresses, and probably a different spelling of their name. In these instances, you will want to merge those two accounts into one. Here is a step-by-step guide through that process.
Open the Terminal window under Shop Tools. Select your store. Once the Terminal Window is open, search for the customer contact that you want to keep.
Begin by searching for the main person. In this example we will merge Larry Jappe and Marj Jappe into one account, keeping Larry Jappe as the correct account.
Select Larry Jappe from the list:
Once we’ve opened the customer account, click on the silhouette in the upper left corner.
Click on Merge Customer in the top left corner.
A new window will open. Here you can search for the other email address/name that you want to merge into the main account.
It will bring up all possible results, choose the one you want. This is what you will see:
If what you see is correct, with the main account in green, then hit Confirm Merge.
Merge is now complete.