Convert group messages to private channels
You can change the members of your group conversation by converting the group message to a private channel. When a group message is converted to private, its history and membership are preserved. Membership in a private channel remains as invitation only.
Any member of an existing group message, except guests, can convert that group message to a private channel.
All group message participants must share at least one team membership.
You can convert a group message to a private channel using a web browser or the desktop app.
To convert a group message to a private channel:
Select the group message name at the top of the center pane to access the drop-down menu, then select Convert to Private Channel.
Specify the team where the new private channel will be created. You’re prompted to specify a team when all group message members share more than one team membership.
Enter a channel name.
Select Convert to private channel.