If you live in the house with your mother then you can most likely refinance it as a primary residence. There is also a provision for it to be your primary residence even if you don't live there but own the home for your elderly parent.
Per Fannie Mae:
"A principal residence is a property that the borrower occupies as his or her primary residence.
The following table describes conditions under which Fannie Mae considers a residence to be a
principal residence even though the borrower will not be occupying the property.
Children wanting to provide housing for elderly parents:
If the parent is unable to work or does not have sufficient income to qualify for a mortgage on his or her own, the child is considered the owner/occupant."
You will need to find an experienced loan officer that really knows guidelines to assist you. I would recommend that you call the following person in your state:
First Century Bank Mortgage
11660 Alpharetta Hwy Suite 225
The other way is to modify the loan. Do not try this yourself. Pay someone to do it. I have 2 professionals that can do this. Cost is about $2500. Depending on the loan amount, this may cost less than refinancing. Do not become late on the payments. It's been believed that you have to be late on the payments to get modified. You actually have more leverage if you're paying on time. Email me for the contact name and numbers if interested. The loan could get lowered depending on the bank, OR the rate may be lowered, OR if an audit finds inconsistencies in the loan process, the loan may be dismissed entirely. Please note that the latter happens in less than 1% of modifications.