Everyone makes mistakes sometimes—or needs to make important additions or updates. Now you can make changes to any message that you've posted to Yammer, no matter what type of message it is or content it contains.
Find your post that you want to edit.
Make the changes that you want to your message and click Save.
Edited appears at the top of the message.
To see any previous versions of a Yammer message that has been edited:
At the top of the message, click Edited.
An Edit History box with previous versions appears.
Click the X in the upper-right corner to dismiss the Edit History box.
This feature is available in the Yammer web experience and in the Yammer iOS and Android apps released after April 13, 2017. You must update your mobile apps to the latest version to see this feature.
Editing is currently not available for Yammer external groups. The ability to change attachments (files, images, Yammer notes) is not currently supported.