There is an easy way to change the pickup address. You will have to follow these simple steps:-
Read Amazon terms for sellers and its policies as regards change of pick up address and corresponding address registered with GST. Amazon is not going to accede to any request that will create conflict with the law for the company. That said, it is possible to change pick up an address but first, in your interest, get this change to reflect in your GST registration certificate just to be on the safe side. Next, you can log in to your seller account, navigate to Easy Ship settings and input the new pick up address.
I do not know why people keep asking this sort of questions. As a seller on Amazon one should be thoroughly familiar with the dashboard and the options and explore all of them to know what can be done and what cannot be done. Still, if you cannot be bothered, here is the answer: log into your account on the seller. Go to settings and then easy ship option and change the pickup address there. That should do it. If the change is not affected then you may have to contact seller support.