The RTS codes file is usually maintained by the dealership.
To edit an existing one, go to Manufacturer System / 00. Global Data > Standard RTS Code
Enter the RTS Code and company number. Search for it using the ... button.
When the record is loaded, click Amend. Update the field/s and click Save.
To create a new one, click Insert > New and enter the required information. Or load an existing one then click Insert > Copy to copy the details and just amend the fields accordingly.
Enter the RTS Code, Company No, Description and other relevant information, then Save.