If you have a meeting published through the Internet Publishing module and you need to notify the public of the cancellation, you can to do this by publishing an "additional document". Here's an example of the output to the public: 

Follow these steps:

1.Go the Internet tab of your Publishing page for the relevant meeting site 

2. Use the up arrow  to "upload" an Additional Document(s)

3. Complete the form with the Document Title (this becomes a hyperlink visible to the public), and choose your file to upload (it can be generic or you can choose to add relevant meeting cancellation details).

4. Publish the Additional Document by clicking the green button as you normally would to publish. Here's what it will look like once published (it's most apparent in List view):

Please Note: you can also unpublish the meeting date link altogether so that the meeting isn't visible.