Refinance Mortgage Loan

How long does a person have to stay for a USDA loan before they can refinance with another mortgage company?
They each took out loans quite a bit back when she was a huge single mother. Now she makes about 80K a year and doing fine. Want to refinance to consolidate debt to a low interest, low payment fixed loan. The prospective mortgage companies will not touch her existing loans due to the fact that it is a USDA loan.
When you find an institution that will buy it and refinance it to you. But you would not be able to express their interest rates. I would suggest that you contact the USDA and see if they could use a moritorium to you for late payments and eventually they may even refinance it for you if you meet their standards for this action.