To Reset PIN on Roku is easy as you simply need to update it for resetting the PIN. During the Roku PIN reset, you will not be asked to enter your older PIN. Thus, you can easily reset this PIN by simply logging into your account. Here is the method to reset the PIN:
Go to the go.Roku.com/PIN reset page
Log in with your Roku account credentials
Select the “Update” button present under the PIN Preferences tab
Choose your new PIN > verify the PIN > Save the changes