Customers and Suppliers module

If a customer is registered without a company code, multiple customers with the same name may be entered. If there are transactions associated with these customers, the customer cannot be deleted, but customers can be merged.
Note: Perform this action carefully, as merging customers cannot be undone.

Select the customers you want to merge — for example, by entering a part of the name in the "Name" field — and activate their rows in the list by checking the boxes. Then, in the toolbar, select the Merge button.

A new window will open where you can complete the merge action: you need to specify which record to keep and which records to merge — only one record can be kept, but an unlimited number of records can be merged.
Once selected, click the "Merge" button.
If there are no issues, the records will be successfully merged. If the merge cannot be completed, a message will appear explaining the reason.