This article explains how to sign out of Netflix on Roku, plus how to sign in to a different Netflix account. The steps will vary slightly depending on your device.
Roku: How to Log Out of the Netflix App
On newer Roku streaming players and smart TVs, it's easy to sign out of Netflix from the app's home screen. If you're not sure which version of Roku you have, try these steps first; instructions for older models are below.
On the Netflix home screen, use the left arrow to open the menu, then press the down arrow to select Get Help.
If these steps don't work, start from the Netflix app and press the following arrows on your remote in this exact order: Up, Up, Down, Down, Left, Right, Left, Right, Up, Up, Up, Up. Select Sign Out, Start Over, Deactivate, or Reset.