Last and first name issue between MRV receipt and DS160 for visitor visa

[lalit1509]

Hi, my mother is not having last name in her passport, therefore when i created her profile then I put UNKNOWN in last name and given name in first now and with same name MRV receipt has been generated. But today I found that in this case people generally uses given name in last name and FNU in first name. I haven't book the appointment yet and I thinking of filling new DS-160 but my worry is how to correct name on MRV receipt. Please help.