Removing FNU from name during citizenship application

[saksham]

My parents green card has their name starting with FNU (First Name Unknown) because apparently the name was not split into first and last name in their passports. We got new indian passports with correct names.
Now they're applying for citizenship. Is it possible to get FNU removed from their name as part of N400 application. We're in San Jose, CA area. I read some posts that San Jose office does not do name change anymore but they do it in some cases like changing last name because of marriage etc. Any suggestions to get FNU removed?

 

[Jackolantern]

What is on their birth certificates? Does it also have FNU or blank for their first names? When there is a name discrepancy, USCIS will look at the birth certificates to sort it out (and any other name change documents including marriage certificates, if any).

If the "FNU" is a mistake, removing it would be correcting a mistake, not an official name change, so they should be able to get it done regardless of their location. They should fill out the N-400 with separate first and last names (without FNU) in the section of the N-400 where it asks for current legal name, and should bring their birth certificates and marriage certificates to the interview to sort it out.