Here's how to replace the YouTube channel in your Thematic account:

1. Login to your Thematic account.
2. Click on your profile photo and select the Switch Channels button.
3. Click the Manage Channels button.
4. Click Replace next to your currently added channel.
5. Follow the steps on the pop-up window to add your YouTube channel. You will be asked to login with a Google account and then select your Brand Accounts / Channels.
6. Your new YouTube channel should now be listed.
7. Click Done to close the pop-up window.

Creators on Thematic Premium can add unlimited YouTube channels to their Thematic accounts. Free users will have access to 1 YouTube channel in their account.