If you create a public notice and send it to your vendors, and later notice a content error or typo or want to add additional information to it, unfortunately there is no option to edit in Bonfire. This is to ensure that vendors receive the most up to date information available.
In this case it would be the best practice to send another public notice, in which you clarify the first, or correct the information that has been sent. This will ensure that vendors receive the notice that you have made changes on the Project in question and they would carefully review the new message.
Please click to learn more about Public Notices