I copied this letter from the web site below i hope it helps you:

Determination of extreme hardship is a discretionary act. In fact, the language of INA §244(a)(1) commits the determination to "the opinion of the Attorney General."? Because extreme hardship is not expressly defined in immigration law, various factors are considered in ascertaining whether a waiver of inadmissibility should be granted. The factors identified as relevant by the Board of Immigration Appeals include, but are not limited to: (1) the presence of lawful permanent resident of United States citizen family ties to the United States; (2) the qualifying relative's family ties outside of the United States; (3) the conditions in the country to which the qualifying relative would relocate and the extent of the qualifying relative's ties to such country; (4) the financial impact of departure from the United States; (5) disruption of educational opportunities; and (6) significant conditions of health, particularly when tied to an unavailability of suitable medical care in the country to which the qualifying relative would relocate. While the list seems lengthy, not all of the foregoing needs to be present in every case.

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A hardship letter for immigration is sent to authorities, basically requesting leniency in cases where immigration status isn't authorized. These letters are usually sent to try to prevent deportation or other punitive actions that would evict the unlawful immigrant. In other cases, hardship letters may be sent for requesting an extension of missed deadlines for expired work visas, green cards, etc.

Look to a free attorney for the most reliable way to get a hardship letter to immigration. An immigration lawyer will know the ins and outs of what information may sway officials in your favor. Even with this assistance, actually writing the letter will probably be up to you.

Always collect as much data as possible to include with the letter. Write up a thorough summary of reasons why you're unable to meet deadlines, or why you're requesting leniency from immigration penalties such as deportation. Be sure to include any health, financial, or other related extenuating circumstances that have contributed to your inability to take the lawful action.

Finally, if the immigration authorities are sympathetic to your hardship, be sure to correct your immigration status quickly. This shows good faith on your part, and proves that you're trying to do the right thing.

A hardship letter is a plea for mercy based on 4 main factors. You are asking the immigration people to let someone in your family come back into the US, or please not deport them or do other adverse things to them.

The 4 reasons that you have to explain are:

(1) physical hardship, such as you need the person to assist you at home because you are disabled, pregnant, or elderly, as examples,
(2) emotional reasons, such as you and the person were married 10 years and have 3 kids, and you're a close-knit family,
(3) psychological reasons, such as you are the person were engaged and about to be married, as another example,
(4) financial reasons, such as the person had a job and was supporting you, your mother, and your 4 kids, and now you have no income and have to apply for welfare and food stamps.

Any, and all of these types of reasons can be used. Many people advise that you consult with an immigration agent for assistance with wording that has worked in the past.

Remember that President Obama recently told the immigration people not to deport anyone unless that person has been guilty of being a criminal while here in the US.

I writing this letter because my husband is going to be deported from USA. My husband made mistakes on the past and he is very sorry about, he paid for his mistakes. I just want to ask you for forgiviness. We have a 15 years old son, he is an excellent student, he loves his father. If we have to be separated for legal reasons, my son will be devasted. I will never want to live in Colombia, thats is my husband country, I won't want my son to live there, is to danger, people get kidnapped all the time for all kinds of reasons. Please, I can assure you my husband do feel sorry for what he did.