Make sure you are signed in to your owner profile and navigate to the list of your room at https://remotehour.com. From here you can click on the three dots next to the room name then select Delete to delete it.
You'll be asked to confirm that you want to delete the room before it's completely removed. When this action is complete all room customization will be removed as well.
Click the Create new Room button, after you have typed in the name of the desired room.