Answer:
Discuss the situation with your supervisor
Step-by-step explanation:
Organisations have a reporting structure that is put in place to share responsibility among employees.
Supervisors have higher clearance to information and greater ability to take decisions that affect the business, while the lower level employees have access to less information and do not have the authority to make major decisions that do not comply with set procedure.
In the given scenario the national sales manager wants a sales bill for items that have not yet been shipped and are not planned for shipment until after this fiscal year.
This is against normal procedure.
To get higher authority to endorse that action you will need to discuss the situation with your supervisor.
The big clients may enjoy exception to the rules and this will need to be endorsed by your supervisor