what is the process (query) needed to change post visibility status
 

We need to be able to execute a query that places posts that include a specified keyword into a moderation queue (the queue provided as part of the Prevent Spam mod).

This involves changing the visibility status of the post and unknown other changes in the database. We have attempted using a query that simply changes the visibility status in the vbpost table. However, the posts do not show up in the queue and they do not display the "posts awaiting moderation" symbol in the threads when viewing the forum list.

Any ideas about how to make this work?

You'll need to look at the moderation table also. If you want threads to show up in the moderation queue, then you need to enter them into there. There are also some counters to do (I think). Look up the function unapprove_post in functions_databuild.php