Allotment of Share to Subscribers of MOA after Incorporation

What if out of three subcsribers one of them does not wish to subscribe for shares? 

Whether share certificate required to be issued to the first directors of pvt Ltd co. And when is pas -3 required to be filed ?

Pas 3 is required for allotment of shares.

Share certificate is issued to Shareholders.

I would like to know if you can reduce the number of allotted allocated to subscribers in the memorandum of association. And what are the steps to take to reduce the allotted share?