When a customer asks to do something that is someone else's job, the most appropriate response is to politely inform the customer that the request falls outside of your role and then either find the appropriate employee to assist them, introduce the customer to the right person, or give them the contact information for that person. Another suitable approach is to escalate the request to a manager who can ensure the customer receives proper assistance. It is important to maintain professionalism, avoid doing tasks that you are not authorized or trained to do, and to help the customer by directing them to the right resource rather than trying to handle the request yourself if it is outside your scope.
In practice, this might involve calling or paging the correct department or walking the customer to the right person, ensuring the customer feels supported but without overstepping your job responsibilities. Being honest, polite, and helpful in guiding the customer is key to managing such situations well.