Hi,
I am perusing PhD in engineering from one of the private university in India, Since starting I have only one supervisor and he is not a regular employ of that university (External supervisor) now when I have submitted my final draft of thesis in July 2017 and all the reviewer comments reached to university. University authority asking me to add one Internal Supervisor from their university as a main supervisor and changed the previous one to co-supervisor. Since I don't have any other way to complete my degree so I tried to convince my previous supervisor to support me, as according to updated UGC-2015 guideline he won't be able to show my name as guided students and their won't be any benefits. But still he is not supporting me and always talk to me very rudely and also warned that if I proceed without taking him in confidence he will spoil my degree by complaining to higher authority. From past few days My life is simply become hell and not getting idea to deal with this situation.

The main problem is that if I change my supervisor and take the another university person as a main supervisor so the examiner who evaluated my thesis is a friend of my previous supervisor, so I am afraid that he will mark some negative comments or he won't come to attend my final presentation.

I am looking for the information that Can I change my Supervisor and Examiner at this stage?

If the university is asking to change supervisor, then that's what you have to do. Speak to your head of graduate school or similar if you're unsure.

But ethically it is not right. Why would your internal supervisor want to take credit for the work that he never did? I think your external supervisor is right!