There's potentially big help here for families who can no longer afford their mortgage payments and are in danger of eviction.

Home Affordable Modification is part of President Obama's Making Home Affordable foreclosure prevention program.

To qualify, you have to be able to show that your income or expenses have changed significantly -- maybe your mortgage rate adjusted, you lost your job or you are paying unexpected medical bills.

You also must live in the home. The modification program does not apply to vacation or investment properties.

You can be behind on your payments, but you don't have to be.

Here's how the process works:

Call the bank or mortgage company you send your mortgage payment to every month. If it is participating in the program, it must screen you for eligibility.

That screening involves looking at your case to determine which would be more costly for the company, modifying your loan or foreclosing on your house.

Here's where there's a huge difference between Home Affordable and the Bush administration's heavily hyped but failed foreclosure prevention programs, such as Hope for Homeowners and FHASecure.

The Bush administration expected lenders to absorb all of the losses of modifying mortgages. Because it was usually cheaper to foreclose, that's what they did.

Obama's plan reimburses lenders for some of the losses they incur when modifying at-risk mortgages. That should tilt the calculation in favor of modifying, rather than foreclosing, for many homeowners.

The goal is to lower a borrower's mortgage payments to no more than 31% of their gross income, a common measure of affordability.

Lenders will do this by lowering interest rates to as little as 2% for at least five years, extending the length of the loan to 40 years and allowing some of the debt to go interest-free.

In extreme cases, they might forgive some of the principal owed on the house, but that is entirely at the bank's discretion.

Once the details are worked out, you'll be put on a trial modification for three months. If you're current at the end of three months, the deal will become permanent.

Your new interest rate will last at least five years. At that point, your interest rate may begin to rise, at a rate of no more than 1 percentage point per year. It will be capped at the prevailing rate at the time of the modification. If you inked the modification deal today, your interest rate would be capped at around 5.5%.

At the end of five years, homeowners who stay current on their payments will have $5,000 knocked off their debt.

If no amount of modification can keep you in your house, there is money in the plan to encourage banks to take other steps to avoid foreclosure, including accepting short sales (in which the bank agrees to take whatever you can get for the house) and deeds-in-lieu of foreclosure (in which the bank essentially takes the keys to the house and calls it a day).

Homeowners who fall into this category may be eligible for $1,500 in relocation expenses.

If you have a lot of debt in addition to your mortgage, you may have to agree to mandatory counseling to help you deal with your debt.

This applies to those who have total monthly debt payments of 55% or more of their gross monthly income after the loan modification. That includes your modified mortgage payment, plus things like home equity loans, car loans or lease payments, credit card debt and alimony.

If you have further questions, go to the government's new Web site, MakingHomeAffordable.gov.

By Mary Yanni

Interest.com Contributing Editor