you cannot adopt your step son as he is 25 years old 

2) further for valid adoption biological father consent is necessary 

You can't change the same in is birth certificate but in other documents you can mention your new husband's name

If once the name of biological father is inserted in record then it can be erased by general course, in case where any one instead of biological father wants the custody of the child then the only way is adoption deed, the person who want the permanent custody of the child can go for registeration of adoption deed, the deed should be entered in between the original or biological parents and adopting parents, in alteration the adopting parents can apply in civil court for the custody or legal guardianship but only when the biological parents are not available.

Dear Sir,

If once the name of biological father is inserted in record then it can be erased by general course, in case where any one instead of biological father wants the custody of the child then the only way is adoption deed, the person who want the permanent custody of the child can go for registration of adoption deed, the deed should be entered in between the original or biological parents and adopting parents, in alteration the adopting parents can apply in civil court for the custody or legal guardianship but only when the biological parents are not available. In this case you cannot adopt your step son as he attained majority.

Dear Sir,

If biological father is not there you cannot change the name of father’s name since because either he is died or otherwise not traced out. The name of the biological father can be changed only when you adopt such child. In  this case since the child is more than 25 years as such you are not allowed to adopt him.

If a child is adopted child by his step father means that is you ?

If yes, then he can published name change saying 'I have changed my name and father name due to adoption' in his state government official gazette. Using gazetted copy he can changed his surname and father's name to second father name in Pan Card and Aadhaar card.

You can file a suit for declaration before jurisdictional civil courts and get decree name of your choice. It is important to make concerned departments as respondents to suit. It normally take 6 months to obtain decree. You can contact me for further details. 

Dear Sir, 

- Adoption of an adult is not valid.

- In your case, you can go for adoption deed with fact that you have married his mother with consent of biological father. 

- Once you get the order in favor, submit the copy of same to all authorities for change. 

Regads

Vivek Arya

A format for the affidavit is given below:

Before the Judicial Magistrate, Court Name

Affidavit

I Mr. ……………………….. S/o ………………………………… aged about ____________ yrs, residing at………………………………. ,do hereby solemnly affirm and state:

That my recorded name in school and college is ______________(YOURNAME), but I myself popularly known as _________________(New name).That after the completion of my studies I want to start a business in IT Sector. From the numerology point of view; I came to a conclusion that the business in my nickname as in the name of NICKNAME will helpful for my endeavours.That by virtue of this affidavit, I changed my name from YOURNAME (old name) to CHOSENNAME (new name) and henceforth I shall be known as the CHOSENNAME (new name) for all purposes.That the facts stated above are true to the best of my knowledge and belief.

Identified by-

Advocate Deponent

CERTIFICATE

Certified that the above named deponent being identified by ______________( ADVOCATE NAME), do hereby solemnly affirm his knowledge and belief.

Place:

Date:

Notary Public, City Name

Step- II:

Publication in the Newspaper

The next step is to publish an advertisement in two newspapers- one in the official vernacular language and the other in English.

This is done to publically declare the change in the name so that if a conflict arises later, you have an official declaration of your name change.

Preserve the copies of the newspapers very carefully as well its scanned copies.

A sample copy of the format is as follows:

I, Mr./Mrs.____________ (old name) have changed my name from __________________ (old name) to ______________ (new name) by an affidavit sworn before the Notary Public, ______________ (place) on _________ (date). Henceforth, I shall be known as _________________ (New Name) for all the purposes.

 ______ (Name) and ________ (Complete Postal Address).

Full Signature

Step- III:-

Notifying in the Gazette

The next step is to get your name published in the State/ national gazette.

Go to the department that looks after the Gazette publication, the Government Press, in most of the cases.Fill the “Deed changing surname Form” and fill it very carefully following all the instructions mentioned onThe name changing notification will then be published in the Gazette and you’ll receive its copies in the mentioned address in the Deed Form.

With this, the name change procedure gets officially completed.

 The documents required for Name change in gazette for Major / Minor:

For Major / Adults (Mandatory Documents)

ID Proof : Pan card or Passport or Driving Licence or Aadhar Card or Voters IdAddress proof : Ration Card or Aadhar Card or Electricity Bill
Photo : One Passport Size PhotoApplication Form : Duly Signed Application Form with all details & reason for Name change

Optional:
Marriage certificate ( if Any for Female after Marriage)
Affidavit ( If Any Made for any reasons like Adoptions etc.)
Divorce papers (In case of Divorce) etc.

For Minor below 18 years (Mandatory Documents)
ID Proof: Aadhar card or School ID or Aadhar Card
Address Proof: Ration card or Aadhar Card
Age Proof: Birth Certificate or School LC or Bonafide
Photo: One Passport Size Photo
Application Form : Duly Signed By Minor if possible and parents or Guardians

Step- IV:-

Getting official documents changed

After you have successfully changed your name, you will have to update you official official documents (e.g.-Passport, PAN Card, Driving License, and Ration Card)

The good news is that your copies of the affidavit, Newspaper publication and the Gazette notification are enough to get these documents changed.

For changes in Passport, you need to fill the following form:For changes in the PAN card, you need to fill the following form:For changes in the Bank Accounts:

Copy of the affidavit and the gazette notification is needed.

You will also need no objection letter from biological father also

Dear Client,

Not possible. This could have done through adoption but since the child crossed 21 years of age. He can`t be adopted.

See since now child is major he cannot be now adopted if there is no custom of shooting major in your community so therefore the name of biological parent can not be changed.

The name of the biological father can not be changed in the birth certificate 

Rest the name can be changed in other ID's easily. 

When did you married the second wife? 

The biological father remains the biological father for all practical reasons unless the child is given in adoption by him to someone else. Hence, his name cannot be changed.

The name of the biological father can be changed in the register for births with the local authority only if there is a valid and registered adoption deed for having adopted the child.

Since your step son is 25 years of age you cannot adopt an adult even if his biological parents are ready and willing to give him in adoption to you, hence there is no possibility to change the father's name of the child for any reason.

No records can be altered or his original father's name can be replaced with your name to the step son's father;'s name.

There is no provision in law for that.