Editing and Deleting Messages
If a message contains spelling mistakes or doesn't meet your grammar requirements then you can edit them.
Press the edit icon next to the message and you'll see the message expands and allows you to alter the text.
When you're happy with the changes simply press update. The alterations will be applied in the list and on participants devices if it's a message that's currently in the published list.
You also have the option when in the editing view to delete the message entirely. Be careful when you do this because there is no going back from deleting a message, when it's gone it's gone. If you aren't quite sure it might be safer to put it in the archive list for the time being.