In order to adopt agile practices in any meaningful way, you have to change your organization.
This includes the members of the team, the people who describe and prioritize work, and the executives who hold everyone accountable for the outcome.
In order to drive that kind of change, you need authority commensurate with your responsibilities.
But you also need influence with people over whom you have no authority. Who may, in fact, have authority over you.
The best path to this is integrity. Be the same person in all contexts. Accomplish things for people. Keep your word.
Never assume you’re entitled to trust. Earn it. Work toward a shared definition of success and continue to earn trust as you progress through your change program.