Question

Why do the signers of the declaration think it is their duty, as well as their right, to change their system of government?

Answer 1

They thought it was their duty and their right, simply because it was. The signers wanted to create a new system, a new government, a new world, and they knew that a key step in getting what they wanted was a declaration. They are the people that founded their country and made it both a duty and a right.