Some basic works about a common salesman

If a salesman already has some regular customers who need to be maintained ,then his/her main job is to do business with these old clients, not to prospect for new business. I say this for a reason that there are too many things in detail to take care of  for a salesman to maintain good relationships with the current customers. Some following regular stuff need a salesman to do before a computer everyday, like checking the delivery date of goods customer required, making offers when the customers’ inquiry coming, namely offering a quotation, making a lot orders when the customers placing a large quantity of orders, in addition, a salesman has to track the latest situation about the customers who have got the salesman’ s offers, and report the new information about the quotations to the sale manager or directors. How could a  salesman be approved by the customers and the sale managers? It up to the salesman oneself.