Your Pro subscription is related to the email address you used to create your PhotoRoom account so you can cancel the auto-renewal and resubscribe with your new email address

Your Pro subscription is related to your Store account (Apple or Play Store). You can create a new PhotoRoom account using a new email address as long as you're still logged into the Store's account you used to make the purchase

If you want to change your email address related to the Store you used to subscribe to, you can cancel the auto-renewal and resubscribe