Background
There are many situations where it is useful to have more than one person who is able to post to a Delta Chat channel. Common use cases include:
- chatmail relay operators
- local communities
The current implementation has a 1:1 between the profile creating the channel and the channel itself, but there is a straightforward way to share a profile among a group of trusted people, even without being in the same place/local network 
How to create a Delta Chat channel with multiple “admin” operators
- Create a new chatmail profile. You can even give it the same name as the channel you want to create
- Create the channel with the profile created at step #1
- Create a backup from the profile menu at Settings → Chats → Export Backup
- Save the backup file on your device and use a secure way to send it to other trusted people who should be able to post into the channel
- Have other people recover the backup on their device and the profile will be fully operational