Changing One Time Customers

Hi All,

I check the forum and unable to find answer to my question.

My client creates sales inquires on daily basis for many customers (who are not regular). So We can maintain One Time Customer Account Group for them.

But if any of the customer again comes back and gives a purchase order to client, then he should be added to regular customer with all details.

So can we do this? If so please let me know the process.

Thanks a lot in advance.