Hi @KarimA,
Thanks for sharing your first post in the Roku Community!
We understand that you would like to unlink the Roku Mobile App from your sister's phone. We'd like to investigate and help you out. We'll forward this to the appropriate team for further investigation. In the meantime, we need some additional details for the escalation. For us to expedite the issue please provide us with the Roku Mobile App version by going to the App > then go to Account > and tap Help and About.
Once we receive this information, we will be able to forward it to the appropriate team so they can conduct a thorough investigation.
Please don't forget to ask for assistance if you have further questions.
All the best,
Emman
Emmanuel-D.
Roku Community Moderator