This Article describe how to merge two customer can be one customer
if you can trouble with duplicate customers contact with different invoice, you can change invoice get one customer or same people
And Report with different name customer will be merge by customer same name
1. Check your contact customer if you have two data customer with same name customer
"contacts - customers" .
"Order - Customer Invoice"
3.Now you can merge customer - "Tools - Merge Customer",Input your name data old customer with new name data customer "get rid of duplicate name customer" then choice Process
4. Done you can get rid of duplicate name customer, invoice