A notice of intent to deny or NOID is a formal statement from USCIS that it has determined that the applicant is ineligible for the immigrant benefit requested. However, the USCIS will grant the applicant an opportunity to overcome this determination and demonstrate that he or she is eligible.
A notice of intent to revoke or NOIR is a formal statement from USCIS that is has determined that a previously approved application was approved in error or that the applicant was never qualified to the immigration benefit, typically due to alleged fraud or misrepresentation by the applicant. USCIS will grant the applicant an opportunity to respond to the NOIR to defend the revocation.