As customer accounts become out-of-date it is possible to remove them from the Sales Ledger.
You can only delete a customer account when there are:
If you cannot select Delete on the customer account, there are still transactions attached to the account.
Note: If the account is a head office account, with related branch accounts, only the head office account is removed. You will need to remove branch accounts independently.
You must:
Open: Sales Ledger > Sales Accounts > Amend Account Details.
Reference
Delete sales and purchase transactions
Delete archived transactions (Sales Ledger)