According to http://www.uscis.gov/files/pressrele..._AC21_8403.pdf on page 3:
Subject: Guidance for Processing Form I-485 in Accordance with Section 106(c) of AC21
As discussed above, if an alien is the beneficiary of an approved Form I-140 and is also
the beneficiary of a Form I-485 that has been pending 180 days or longer, then the approved
Form I-140 remains valid with respect to a new offer of employment under the flexibility
provisions of §106(c) of AC21.
Accordingly, if the employer withdraws the approved Form I-140 on or after the date that
the Form I-485 has been pending 180 days, the approved Form I-140 shall remain valid under
the provisions of §106(c) of AC21. It is expected that the alien will have submitted evidence to
the office having jurisdiction over the pending Form I-485 that the new offer of employment is
in the same or similar occupational classification as the offer of employment for which the
petition was filed. Accordingly, if the underlying approved Form I-140 is withdrawn, and the
alien has not submitted evidence of a new qualifying offer of employment, the adjudicating
officer must issue a Notice of Intent to Deny the pending Form I-485. See 8 CFR
103.2(b)(16)(i). If the evidence of a new qualifying offer of employment submitted in response
to the Notice of Intent to Deny is timely filed and it appears that the alien has a new offer of
employment in the same or similar occupation, the BCIS may consider the approved Form I-140
to remain valid with respect to the new offer of employment and may continue regular
processing of the Form I-485. If the applicant responds to the Notice of Intent to Deny, but has
not established that the new offer of employment is in the same or similar occupation, the
adjudicating officer may immediately deny the Form I-485. If the alien does not respond or fails
to timely respond to the Notice of Intent to Deny, the adjudicating officer may immediately deny
the Form I-485.
If approval of the Form I-140 is revoked or the Form I-140 is withdrawn before the
alien’s Form I-485 has been pending 180 days, the approved Form I-140 is no longer valid with
respect to a new offer of employment and the Form I-485 may be denied. If at any time the
BCIS revokes approval of the Form I-140 based on fraud, the alien will not be eligible for the
job flexibility provisions of §106(c) of AC21 and the adjudicating officer may, in his or her
discretion, deny the attached Form I-485 immediately. In all cases an offer of employment must
have been bona fide, and the employer must have had the intent, at the time the Form I-140 was
approved, to employ the beneficiary upon adjustment. It should be noted that there is no
requirement in statute or regulations that a beneficiary of a Form I-140 actually be in the
underlying employment until permanent residence is authorized. Therefore, it is possible for an
alien to qualify for the provisions of §106(c) of AC21 even if he or she has never been employed
by the prior petitioning employer or the subsequent employer under section 204(j) of the Act.
Does it mean, if I switch jobs after 180 days I-485 has been applied, being I-140 approved, even if old employer revokes I-140, it remains valid and I am safe as long AC21 has been invoked and USCIS has been notified?
This memo has been published on Aug.2003, is it still valid?