Most immigrants to the United States come with the help of a sponsor, either an employer or a family member who petitions the government for the immigrant to be allowed in. In addition, many family-based visa petitions are submitted on an affidavit where the current resident agrees to provide financial support while the new immigrant establishes a life here. Sponsors of immigrant petitions or affidavits of support who want to cancel their sponsorship can do so. The right course of action depends on how far along the immigration process the application has traveled.
TL;DR (Too Long; Didn't Read)
You can revoke the immigration petition, initiate rescission proceedings or even report the immigrant for deportation. Revoking the petition is easiest but must be done relatively quickly.
Revoke the Petition
You can attempt to revoke the immigration petition if you want to cancel your sponsorship. The easiest way to put a stop to a sponsorship is to cancel the immigration petition before it is even approved. An individual who has filed the original I-130 or I-140 petition can contact (United States Citizenship and Immigration Services (USCIS) in writing to revoke the petition.
Because most immigrants are unable to petition on their own behalf, the cancellation has the effect of ending the immigrant's chances of getting the visa. Mail your notice of revocation to the USCIS officer currently handling your case. That officer will find the petition and recall it for processing of the revocation.
Initiate Rescission Proceedings
If a green card already has been issued, there's no way to revoke the I-130 or I-140 petition. In this case, the next step would be for USCIS to rescind the immigrant visa that was previously approved.
Rescission is available only if USCIS learns that the immigrant was not eligible for adjustment to permanent resident at the time of adjustment. The officer can give notice to the immigrant and schedule a hearing before an immigration judge. If the judge agrees that the immigrant was not eligible for adjustment, the immigrant must surrender his green card. If you believe that the original petition was flawed, bring the facts supporting your belief to the attention of the nearest USCIS field office.
Report to the Authorities
You can also report the immigrant to the authorities for removal proceedings. If the immigrant is already here in the country and his green card cannot be rescinded, the next most likely method for revoking sponsorship is to report any grounds for removal. This used to be called deportation.
USCIS will then investigate. For example, if the immigrant has turned to a life of crime, the service might initiate removal. The grounds for removal are specifically set out in law, and the decision on removal will depend on whether USCIS brings a case and whether the immigration judge agrees.
Revoke the I-864
There are some very rare circumstances under which a financial affidavit sponsor can revoke the I-864 affidavit of support. The affidavit lasts until death, until removal of the immigrant, or until the accumulation of 10 years of solid work history after immigration has been granted. You can sometimes speed up the process of the I-864 lapsing from legal effect by encouraging the immigrant to depart the U.S. for more than one year or by encouraging the immigrant to accumulate 10 good years of work history.
It's All About Timing
The most important deadline is the decision to admit the alien for immigration so time is of the essence. After the petition is granted, the process of revoking sponsorship is much more difficult and relies on the immigration court system. This can be time consuming and unpredictable.