Simply Factory Reset the device. During setup, make sure to use the same email address as your other Roku account so everything is linked to that account. Just make sure you have a working Roku remote before factory resetting any Roku device.
To Factory Reset, either press and hold the Reset button on the device (sometimes a little pinhole), for 30+ seconds. Otherwise, Settings/System/Advanced System Settings/Factory Reset.
After a factory reset, you will be setting the Roku up as though it were a new unit right out of the box.
If you have a Roku account already you can link to it via entering the email account on the account. If not you can create a new account
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well. If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X