To switch accounts while activating YouTube TV, start by signing out of your current Google account on the device. Then, visit tv.youtube.com/start on a web browser. Enter the activation code displayed on your TV screen. When prompted, sign in with the desired Google account. Ensure this account has an active YouTube TV subscription. If you’re using a shared device, you can manage accounts by selecting your profile icon and switching to the correct one. Restart the activation process if needed to ensure the correct account is linked.