If your course sections have been incorrectly combined, you can the Moodle support team (moodle@bilkent.edu.tr).
The Moodle admins will delete the parent “metacourse” to free up the “child” section courses for recombination.
Before you contact support, please back up and download any content you have added to the combined metacourse course, so you can restore it to the new one.
WARNING! You must try to correct any combination mistakes ideally before the start of the semester and definitely before students upload work to your course. Even if you have backed up your course, there will be no “user data” in the backup. Therefore, backing up and restoring the course will therefore lead to students losing submitted work!