Create new Parent and Copy Child record from an Existing Child Record

I have two tables that are working together.

Table 1 = Parts Requests (Parent)
Table 2 = Parts (Child)

The Parts Requests table is used in 2 ways. 1. When a customer calls and asks for a quote for parts and 2. When we request a quote for a part from a vendor. 

The functionality I am looking for is this. If I have a Part Request from a customer (Scenario 1) that has a/some parts on it, I would like each of those child records to have a button to generate a new request. The new request will be scenario 2 above where we are requesting a quote for that part from a Vendor. 

Ideally, this button would generate a new Part Request checked off as a Vendor Request, and then it would also create a child record that is identical to the one I clicked the button on. 

This way when the request for a quote from a vendor is created, they don't have to enter the part information again. 

Any thoughts on how I can set up this button would be greatly appreciated!