How can I remove myself as an admin of a group? There is a group that I was a member of. Suddenly one day, all of a sudden I became admin of a group.

How can I remove myself as an admin of the group? And how can I make someone else an admin of that group?

Any help appreciated.
Long press the group chat and hit "Delete and exit group" - your chat will be deleted and you will be out of the group. Someone else will be auto-selected as the group-admin in your place.