Process to cancel the contract without generating billing

Hi Friends, 

What is the proper procedure in E1 to avoid the generate unnecessary Invoice in Service and warranty contracts? I know that if the amount is already billed then system will calculate the cancelation amount on the basis of days left and daily amortization rate. Still if we do not want to get the invoices (-ve RI) while canceling the contract then is there any way to do this?

A simplified scenario as follow :

1. A new contract to customer with amount $1,200 for 12 months amortization.

2. E1 will process amortization every month with amount $100 on first 7 months

3. Now the contract is transferred to a local vendor on the 8th period to continue providing service to the customer