You can delete conversations from your Inbox when you no longer need them.
You can also delete individual messages from a conversation instead of deleting the entire thread.
Click the Delete icon.
Note: You can only delete your copy of the conversation. You cannot delete the conversation for all recipients.
Select the OK button to confirm deletion. All messages from that conversation will be deleted.
Note: New messages sent to you by any participant in a deleted conversation will still appear in your Inbox.