Best way to deal with product change on active subscription?

Best way to deal with product change on active subscription?

Hi, 

We are currently replacing a lot of old product types/subscriptions on our customer base. 

How do we handle this the best way in Billings?

I do not want to Cancel current subscription because it will be treated as Churn. I just want to change the product type and plan (not only plan) - how do you do this currently?