Visitor Visa for my parents..please help

[lydia]

Hi,
i am on H4 and my husband is on H1,so he is planning on sending the documents for my parents for applying for visitor visa. Both my parents are govt employees and so they have their own last names.(eg: dad's(ABC) and mom's(XYZ) )
i have a younger brother who is studying in the united states. Now in my passport and my brothers passport my dad's last name is(ABC) and my mom's last name is(XYZ)

Last year when my parents applied for passport, the people there, asked them to change my mom's last name to my dad's last name. and so now in my mom's passport, my mom's and dad's last names are same( ABC)
but in my dad's passport, my mom's and dad's last names are different(dad's(ABC) and mom's(XYZ)

My mom also got a 'no objection letter' from her work place and in that her last name is (XYZ)..
Can you please let me know whether i should change my mom's last name from XYZ to ABC ??. should both my parents need to have the same last name for applying for the visa?? Please let me know
Thanks alot

[immihelp]

You are parents are not required to have the same last name.

As long as you consistently use the name as per each person's passport, everything is fine. If your mother still uses her maiden name in some of the documents, she can produce her marriage certificate explaining two names. And in Form DS-156, add the second name under the field 'Other Names Used'.