Not interested in the nitty gritty, the following article helped me understand what i wanted to know, especially the quoted lines about Judiciary's role in amendment process
'Article 239 also entails that no amendment of the Constitution shall be called in question in any court on any ground. It should also be noted that according to this Article, there is no limitation on the power of the Parliament to amend any provisions of the Constitution.'
http://courtingthelaw.com/2015/06/18/faqs/amendment-process-in-the-constitution-of-pakistan/
12th April, 1973
Preamble
Whereas sovereignty over the entire Universe belongs to Almighty Allah alone, and the authority to be exercised by the people of Pakistan within the limits prescribed by Him is a sacred trust;
And whereas it is the will of the people of Pakistan to establish an order :-
Wherein the State shall exercise its powers and authority through the chosen representatives of the people;
Wherein the principles of democracy, freedom, equality, tolerance and social justice, as enunciated by Islam, shall be fully observed;
Wherein the Muslims shall be enabled to order their lives in the individual and collective spheres in accordance with the teachings and requirements of Islam as set out in the Holy Quran and Sunnah;
Wherein adequate provision shall be made for the minorities freely to profess and practise their religions and develop their cultures;
Wherein the territories now included in or in accession with Pakistan and such other territories as may hereafter be included in or accede to Pakistan shall form a Federation wherein the units will be autonomous with such boundaries and limitations on their powers and authority as may be prescribed;
Therein shall be guaranteed fundamental rights, including equality of status, of opportunity and before law, social, economic and political justice, and freedom of thought, expression, belief, faith, worship and association, subject to law and public morality;
Wherein adequate provision shall be made to safeguard the legitimate interests of minorities and backward and depressed classes;
Wherein the independence of the judiciary shall be fully secured;
Wherein the integrity of the territories of the Federation, its independence and all its rights, including its sovereign rights on land, sea and air, shall be safeguarded;
So that the people of Pakistan may prosper and attain their rightful and honoured place amongst the nations of the World and make their full contribution towards international peace and progress and happiness of humanity :
Now, therefore, we, the people of Pakistan,
Cognisant of our responsibility before Almighty Allah and men;
Cognisant of the sacrifices made by the people in the cause of Pakistan;
Faithful to the declaration made by the Founder of Pakistan, Quaid-i-Azam Mohammad Ali Jinnah, that Pakistan would be a democratic State based on Islamic principles of social justice;
Dedicated to the preservation of democracy achieved by the unremitting struggle of the people against oppression and tyranny;
Inspired by the resolve to protect our national and political unity and solidarity by creating an egalitarian society through a new order;
Do hereby, through our representatives in the National Assembly, adopt, enact and give to ourselves, this Constitution.
