how to change in additional family information after citizenship

[Gidra]

I have to ask that How can I get my additional family information changed. When I was applying my immigration case my mother told me the dates of birth of my younger brother and sisters which I wrote in additional family information But those were differ from those dates of birth which they have their school records. In Pakistan that date of birth is considered true which is written  on matriculation certificate and this date of birth appears on National ID card and Passport. I have 9 siblings and have to make change in 3 brothers and sisters' record. How do I get it changed. One of my sister took birth after I got Immigration.
Please let me know.
Regards.