Open the 
Service Credit
Memo window.
Press F3 to create a new credit memo.
Fill in the No. field.
In the Customer No. field, enter the number of the customer in the service contract.
You can use a contract service credit memo when a customer cancels a prepaid service contract or removes a service item (a contract line) from a prepaid contract. You can also use it to correct an erroneous service invoice.
Open the Service Credit
Memo window.
Press F3 to create a new credit memo.
Fill in the No. field.
In the Customer No. field, enter the number of the customer in the service contract.
On the Invoicing tab, you can see further information that the program copied from the customer card. If you want to post the credit memo to a different customer than the one specified on the General tab, enter the number of that customer in the Bill-to Customer No. field.
You can compare the credit memo to the original posted document, for instance in the Posted Service Invoices window.
In the Posting Date and Document Date fields, enter a date.
On the credit memo lines, enter information about the items that have been returned or removed, or the allowance that will be sent. You can also choose to use the Get Prepaid Contract Entries batch job.
If you remove contract lines from a service contract that has been invoiced, the program can automatically create a credit memo. If the Automatic Credit Memos field on the Invoice Details tab in the Service Contract window contains a check mark, the program automatically creates a credit memo when you remove the contract lines. If the field does not contain a check mark, the program automatically creates a credit memo when you click Functions, Create Credit Memo in the Service Contract window.