Form I-751, Petition to Remove Conditions on Residence, is intended for conditional permanent residents to apply for removal of the conditions on the permanent resident status and thus to become lawful permanent residents. It is applicable when your conditional residence is based on your marriage or your parent’s marriage to a U.S. citizen or permanent resident.
Form I-751 is a joint petition, you and your spouse have to file it to USCIS together (however, there may be exceptions). Petition to Remove Conditions on Residence must be filed within the 90-day period before your 2-year conditional green card expires, otherwise there is a risk to be deported from the US.
In most cases, after filing Form I-751 a conditional resident will be required to attend a biometrics appointment and the couple may be summoned for an interview. Once Form I-751 is approved, a conditional permanent resident will become a lawful permanent resident and receive a 10-year green card.
Usually the process of obtaining the approval on Form I-751 takes 5-12 months. The time frame can vary based on the USCIS case load, the USCIS office where you filed, and your ability to properly file the accurately prepared form.