You can edit message that you have posted in timeline conversations and task comments. You can only edit your own messages.
To get start editing a message, click on the three dots to open the conversations options, and select edit message.
Your current message will be selected and you can edit it at will. You can simply add some text or change the current message, add files and links, and even use the embedding capabilities.
Once you are happy with your message, click the “save changes” button, or use the keyboard shortcut ctrl+enter (cmd+enter for mac) to post your edited message.
Your new message will appear as (edited), and when you hover your mouse over it will show the time and date of the last edit.
Note that a few things will not happen when editing a message:
@mentions will not trigger notifications
no notifications will be sent
the message will not go up in the timeline
So in order to get noticed, you need to comment on the conversation that the message has been edited. Doing this will allow you to send @mentions and will also send notifications to the people already involved in the conversation.
Conversations and task comments
You can also edit your conversation comments, as well as your task comments. It works the same way as described above.