Repair process

Dear All,

I have a scenario of a service industry .the organisation has techinncian for carrying out the service of the defective products .Spares are given in advance to these technicians for the repair purpose .

After the repair is over the defective parts are submitted by the technician at the company godown .

At the end the bill is raised by the company to the end customer

Can any one tell me how to map this process..

Regards

Satish