So problem is mothers name on the passport.  That will continue to exist.  You cant change original mothers name.  Helping Hand suggests that love and affection are more important than changing a name on a document, better concentrate on that than breaking head about who is mother on paper.

Thank you for your reply, not much of a help though.

I completely agree with you that love and affection are paramount, we believe the same... and practice to the best of our abilities. However the legal side of things doesn't care much about emotions, you being a lawyer would know better.

Without the legal documents there are multiple real world problems, access to better education is linked to parent being a citizen, sponsership of VISA, social security benefits, and many more.

As I said earlier we would "prefer" to change the name on passport, just to not put our daughter under stress, if avoidable... she believes her step-mother is her real mother... we will to tell her when shes a bit mature.

Thanks again.

Check guidelines at:

https://cara.nic.in/InnerContent.aspx?Id=138#Guidelines for Adoption

https://cara.nic.in/InnerContent.aspx?Id=72#Adoption Procedure

Some NGO's can help you to understand both: do's and don'ts.

https://www.indiaparenting.com/adoption/4_1347/adoption-rules-in-india.html

https://www.sanyog.org.in/Frequently%20Asked%20Questions.htm

https://www.indianmomsconnect.com/2016/02/17/adoption/

If one of the prospective adoptive parents is foreigner and other is an Indian, such case shall be treated at par with Indians living in India.