A person with ID @person and MOB +969123456789 has a channel named TEST in Telegram (for example). This channel has 3 administrator. @person, unintentionally deactivate his account. This means creator of channel deleted. How @person can became the creator of same channel now?
As long as I know there is no such possibility. This is a Telegram platform shortage and you FOREVER miss all creator privileges as soon as the creator account deletes.
P.S: I've contacted Telegram support regarding this issue several times but they never replied. It looks like they would rather be more interested in developing fancy features(like games, etc) compared to solving critical platform shortages.