What happens to the permanent residency process if I change facilities now?

My Labor Certification (or I-140 Petition) has been approved, but I'm not happy in my present facility. What happens to the permanent residency process if I change facilities now?

Prior to AC21 (American Competitiveness in the 21st Century), if you had a Labor Certification approved and have moved to a completely new area or region, you would have been in BIG trouble. Labor Certifications are tests of local markets, thus a person was required to remain in the same locality until final residency was approved, or the process would have had to begin all over again.

Now, thanks to AC21, certain adjustment applicants may change employers within the same or similar profession without disrupting his/her pending adjustment.