Removing the Conversation Tab is being reviewed by the feature team.
For deleting chat messages, please following progress here: https://microsoftteams.uservoice.com/forums/555103/suggestions/33535006.
An error occurred while saving the commentAnonymous commented
Please allow deletion of chats, as can be done for emails, spam, calendars, meetings, word docments, xcell files, folders, wiFi networks, drivers, applications,etc. Or should we delete teams and reload...