In Billing API during the free trial itself, can I move my user to the paid plan

[Jacob_Product]

Hi,
I have an app where I want to give a free trial to my users for 14 days. During this free trial period, the customers would be provided with 1000 credits. Once the users exhaust this limit during the free trial period itself, I want to move users to the Paid plan seamlessly since they had already approved the app charges during the installation process.
Is there any way to do this during the free trial period itself using the billing API?
Thanks