USCIS has posted an update to the Adjudicators Field Manual on September 12, 2006

Page 27 states:

"(1) Determining the Priority Date. In general, if a petition is supported by an individual labor certification issued by DOL, the priority date is the earliest date upon which the labor certification application was filed with DOL. In those cases where the alien's priority date is established by the filing of the labor certification, once the alien's Form I-140 petition has been approved, the alien beneficiary retains his or her priority date as established by the filing of the labor certification for any future Form I-140 petitions, unless the previously approved Form I-140 petition has been revoked because of fraud or willful misrepresentation. This includes cases where a change of employer has occurred; however, the new employer must obtain a new labor certification if the classification requested requires a labor certification (see the section on successor in interest)."

8 CFR 204.5(e) states:

"A petition approved on behalf of an alien under sections 203(b)(1), (2), or (3) of the Act accords the alien the priority date of the approved petition for any subsequently filed petition for any classification under sections 203(b)(1), (2), or (3) of the Act for which the alien may qualify. In the event that the alien is the beneficiary of multiple petitions under sections 203(b)(1), (2), or (3) of the Act, the alien shall be entitled to the earliest priority date. A petition revoked under sections 204(e) or 205 of the Act will not confer a priority date, nor will any priority date be established as a result of a denied petition. A priority date is not transferable to another alien." (Emphasis added).

This regulation says a priority date will not be retained for a petition revoked under section 205 of the Act. Section 205 of the Act states:

“The Secretary of Homeland Security may, at any time, for what he deems to be good and sufficient cause, revoke the approval of any petition approved by him under section 204. Such revocation shall be effective as of the date of approval of any such petition.”

This encompasses revocation for any reason, not just for fraud or willful misrepresentation. The regulations interpreting INA 205 further state, at 8 CFR 205.1(a)(iii)(C) that an I-140 petition shall be automatically revoked “Upon written notice of withdrawal filed by the petitioner, in employment-based preference cases, with any officer of the Service who is authorized to grant or deny petitions.”

Thus, under the law and regulations, when an employment-based I-140 petitioner withdraws an I-140 petition because the beneficiary no longer works for him or her, USCIS automatically revokes the petition which triggers 8 CFR 204.5(e), stating that the revoked petition does not confer a priority date.