This is quite good news  regarding withdrawal and revocation of I-140. Based on the Matter of V-S-G Inc, USCIS will now inform both petitioners and beneficiaries on Notice of Intent to Revoke (NOIR) and Notice of Intent to Deny (NOID. However the beneficiaries will have to have duly filed an AC 21 supplement J. See complete memo below.

Policy
” On November 11, 2017, USCIS adopted as a matter of policy the AAO’s decision in Matter of V-S-G- Inc., which held that beneficiaries who have properly ported under AC21 are affected parties who are entitled to receive notices pertaining to the potential revocation of the approval of an immigrant visa petition due to their ability to port that petition to new employment and a new employer. Now, when USCIS sends a notice of intent to revoke (NOIR) an approval or notice of revocation (NOR) for a Form I-140 (Immigrant Petition for Alien Worker) to the original petitioning employer, we will also inform the beneficiary of that petition in certain circumstances. Beneficiaries will receive such notice in cases where they have filed a Form I-485 (Application to Register Permanent Residence or Adjust Status) and that I-485 has been pending for 180 days or more and they have already properly requested to port to a new employer.1 As of January 17, 2017, eligible beneficiaries must notify USCIS of their intent to port to new employment by filing a Supplement J to Form I-485, found at https://www.uscis.gov/i-485supj. If the beneficiary ported prior to the implementation of Supplement J, the beneficiary must have affirmatively and properly notified USCIS in writing. USCIS will adjudicate and must make a favorable determination concerning the beneficiary’s porting eligibility in order for the beneficiary to be eligible to receive notices of an intent to revoke or of a revocation. These beneficiaries may file an appeal of or a motion on an adverse decision as an affected party.
Regulations state that USCIS may require the beneficiary to inform USCIS if he or she intends to port and to submit evidence that the new job is in the same or a similar occupation before final action is taken on the pending Form I-485. See 8 C.F.R. 245.25. In light of recent litigation and AC21, USCIS is reinterpreting its regulations governing revocation on notice in 8 C.F.R. 205.2.2 This reinterpretation of the regulations concerning who may participate in visa petition adjudications will now include beneficiaries who have affirmatively and timely demonstrated porting eligibility to USCIS. This reinterpretation, however, is limited only to these beneficiaries.”

2017-11-11-PM-602-0152-Guidance-Beneficiary-Standing-Matter-of-V-S-G