20 CFR §655.462

1. (a)The employer may withdraw a CW-1 Application for Temporary Employment Certification after it has been submitted to the NPC for processing, including after the CO grants certification under § 655.450. However, the employer is still obligated to comply with the terms and conditions of employment contained in the CW-1 Application for Temporary Employment Certification and work contract with respect to all workers recruited and hired in connection with that application.
2. (b)To request withdrawal, the employer must submit a request in writing to the NPC identifying the CW-1 Application for Temporary Employment Certification and stating the reason(s) for the withdrawal.