Process Validation Addendum

Hello Everyone
I need some help currrent validated situation.
One of our custome require us to have additional cleaning validation.
The situation is, we already have the validated process. and our customer review our validation documents. Then they suggest us to have some additional claning validation for the same process. So i have to conduct some test. And I have been told to put it as a addendum to the same validation documents.
I do know if there is any special draft for conducting additional test to include in the validation document (PPQ)

Does any one have draft or tamplate for addendum for PQ. Or suggest me what should I include.

Dear Mr.Mehta,
please try to keep your document as simple as possible, you only make simple addendum that what you do and simply link with older one and make final statment that overall process stand validated