When to File Form I-751?
It is important to file Form I-751 within 90 days before your conditional green card expires. While submitting your petition to remove your conditional status, it is always better to file it at the early end of the 90-day period. Do not file Form I-751 before the 90-day period because if you file too early, the USCIS will most likely return your I-751 application.
Who May File Form I-751?
If you are still married, you can file Form I-751 jointly with your US citizen or permanent resident spouse through whom you got the conditional permanent status. Should you have dependent children (on a K-2 visa) who got their conditional permanent status when you did and they entered the US within 90-days of your arrival, you have to include their names in your petition. If your children got their conditional status 90 days after you got or adjusted your status OR if the conditional permanent parent dies, they have to file Form I-751 separately to remove the conditions.
You can apply for a waiver for joint filing, if your spouse died or your marriage ended because of divorce or annulment. But you should be able to prove that you entered the marriage with honesty and good intentions. You can also get a waiver of joint filing if you are able to prove that you entered the marriage in good faith and have remained married, but have been battered or subjected to extreme cruelty by your US citizen or permanent resident spouse or the termination of your status would result in extreme hardship.
Waiver requests for joint filing should be sufficiently backed by adequate proof to support your request. Copies of you divorce decree or police, court or medical proof that you were abused or a death certificate showing that you spouse died are few of the important documents required.
Two passport-style photographs for you and children applying with you should also be a part of the package. Apart from these, two completed fingerprint cards (Form FD-258) for you and any children applying with you and evidence showing that the marriage is a bona fide one and that it was entered in honesty and in good faith should accompany the application. Remember to send the filing fee along.