There are a couple ways, IF the house is not currently in foreclosure. The owner can negotiate a short sale with the mortgage holder. They will tell you the minimum amount they will accept. If they agree, you can sell the house for less than what is owed on it. But be careful, unless it will be included in the agreement from the mortgage holder to accept the loss, they can and likely will come after you for the difference.
If you are the owner of the mortgaged property - then you can find the right buyer and enter into a Tripartite agreement with your mortgagor and the buyer. And after settling the dues, you can execute the sale deed.
On the other hand, if you are the Mortgagor, who is a registered financial institution, you can opt for the remedy under SARFAESI Act or resort to a civil suit for a declaration of title if you are an individual or unregistered financial institution.