Name change for a child after my citizeship with name change

[Vagif]

Me and my wife got our citizenship certificates with new last name. We asked to change the name on the N-400.
Now we have a new last name while our children still have old last name.
What should i do to change their last names ?
Can i request to change their last name with N-600 ?
Or do I have to do court name change prior to getting their passports ?

 

[Bobsmyth]

Likely you'll have to file name change in court to legally change their last name.