An applicant or petitioner may withdraw an application or petition at
any time until a decision is issued by the Service or, in the case of
an approved petition, until the person is admitted or granted
adjustment or change of status, based on the petition. However, a
withdrawal may not be retracted. An applicant who wishes to withdraw a
visa petition (Form I-130, Petition for Alien Relative) should write a
letter to the BCIS office where the petition was filed. The letter
should include the beneficiary's name, date and country of birth, and
A-number or Receipt -number, the date petition was filed, reason for
withdrawing the petition and the petitioner's name, signature and
address. "