既存の個人チャットに誰かを追加することは可能ですか？

[maiki]

@amundo

Is it possible to add users after the initial member set up?

Not currently, but there is a feature request at Add a user to existing personal chat, and I encourage you to share your use case…

@amundo

I often start a group chat to plan something — right now it’s a little online conference/workshop — and I often find myself realizing that I forgot to include someone, or else that someone’s particular expertise might improve the discussion.

…over there.