Click play below: Learn how to manage messages
While you can't delete an entire chat, you can hide a chat from your chat list if it's not relevant to you anymore.
Select the chat you want to hide, then More options > Hide.
If you need to backtrack and delete something you just sent, go to the message and select More options > Delete.
If you require further assistance, please email support@communicatebetter.co.uk or call 0333 043 4000.