A chat record in COYO can’t be deleted in the web interface. This is different in the COYO app, where individual chat messages can be deleted. 

• To delete a message, select the message and briefly press and hold it.
• You will then be given the choice "Copy" or "Delete".
• You then have to confirm this process again.

It does not matter what kind of message it is. You can delete text messages, voice messages, or pictures. A notice that a message has been deleted at that point is always displayed.

Note:
Chat messages can only be deleted via the COYO mobile app, not via the web view.
If a message is deleted, it is of course no longer visible in the chat in the web view.