You have a large amount of customers whose alternate ID is incorrect and you need to change them.
- Create an import file with two columns "Billing Customer Number" and "Billing Customer Alternate ID" (sample below)
- Go to Customers > Bulk import > Browse to the file > Upload > Import Customer Data
|Billing Customer Number||Billing Customer Alternate ID|
|Current Customer Number 1||New Alternate ID|
|Current Customer Number 2||New Alternate ID|
Note: This updates the Alternate Customer ID on existing customers, to complete the initial customer creation additional information is required, see Add Customer Information