If someone proposes to someone then one should think why does he/she wants to be with you. The decision fully lies in your hand whether to accept or reject. Accepting and rejecting both are difficult but while rejecting someone we should not see how does the person proposes but why does he/she does it. Both decisions are to be made by you and you will alone face the consequences so make it to be a good and reasonable decision. After all its your life. And after rejecting someone its not that you disconnect yourself from him/her but try to make the other person understand too.
To politely reject a PhD offer, you can express gratitude for the opportunity and explain your decision respectfully and clearly. It is important to be honest about your reasons for declining the offer and to thank the institution for considering you.
By a veto
A person can reject someone for different reasons. A person reject someone because they do not like the other people or because they like someone else.
Well talk to him politely. Let him see reason with you, he may understand and see reasons with you.
Rerferendum
The consuls did not have the power to reject a government proposed policy. Many a resolution was passed without the approval of a consul, the consulship of Julius Caesar being a prime example. Only a tribune could veto a proposed government policy.
The president can reject a proposed law through veto.
Referendum
ish hfhfpef fh hguherog m
The president can reject a proposed law through veto.
The president can reject a proposed law with a veto.
His power of the veto, and the power he wields at the (supposed) head of his political party.