DELETING A CUSTOM AUDIENCE (THE 180 DAY RULE)
When you delete a CA, you this DOES NOT DELETE your collected data from Facebook servers.
This means you can remove a CA and create one just like it later without losing any data sent to Facebook by the CAE plugin.
The only rule you should have in mind is that the data stored on Facebook (and by Facebook) will expire after 180 days. Again, all of the collected data stored on Facebook will expire after 6 months.
So, if you happen to delete a CA by mistake, don’t panic. Rebuild it and you’re set.