Thank you for your votes and comments on this feature. The team is in the process of finalizing designs for deleting private chat threads. I will update as we have more progress to share.
An error occurred while saving the commentAnonymous commented
These are supposed to be 1-1 private conversations and User should be able to delete messages. If IT admin changes my password and logs in as me then how is this private conversation? Teams brings up all previous conversations when you login as user.