what do you mean by this last term?
It is a modification of the constitution of a polity, organization or other type of entity.
Constitutional amendment
 is a modification of the constitution of a polity, organization or other type of entity.
who said the principles should be made the basis of all future legislation Dr. Ambedkar when was it implemented? 2002 any one reason behind its implementation? Social Justice any one of its features? It aims to create social and economic conditions under which the citizens can lead a good life. did it amend anything? No, but if changes had to be made in the principles it would require a Constitutional amendment.
wiki:19859215
Constitutional amendment [SEP] Introduction
A constitutional amendment is a modification of the constitution of a polity, organization or other type of entity. Amendments are often interwoven into the relevant sections of an existing constitution, directly altering the text. Conversely, they can be appended to the constitution as supplemental additions (codicils), thus changing the frame of government without altering the existing text of the document. Most constitutions require that amendments cannot be enacted unless they have passed a special procedure that is more stringent than that required of ordinary legislation. Examples of such special procedures include supermajorities in the legislature, or direct approval by the electorate in a referendum, or even a combination of two or more different special procedures.