My advice whenever you want change is to have a champion.
The champion should get really educated on agile thinking. Scum, Kanban does not matter, it's more about how to think and how to organize.
The champion is not always right, nor the manager, or special.
Her role is to understand and explain. To make people believe. To win manager and team support. She should not force but question and answer. What is the value? What does the team think? What is the measure? How will it work? Why do you believe this feature will get you that outcome? Listen.
Keep important stuff always at the top. Prioritize. People matter, not process.
Start small, but with full support. One team instead of all teams. Get the success to spread.
The first 3 iterations are usually very difficult. How do you really prioritize so quickly? How do you estimate? What is value? Commitment? Who are the right for the meeting? How do you make sure you don't have long meetings? Believe.
Communicate with people using the highest bandwidth. Face over phone, video over voice, voice over chat, leave email for last. Have short effective workshops focused on goals, never long meetings. Start on time. Always.
Speed things up but don't sacrifice quality. Work in small units and think about interfacing. More important to make a design and implementation that works than to write about it in endless documentation.
Trust. Don't be afraid. Know when it's better to ask for forgiveness rather than asking for permission.
Understand what you're being asked to do, figure out how you're going to do it, ask questions until you understand why you're doing it.
Her role will be key to winning the hearts and minds of the organization and teams, and a successful champion should always adapt.
Scrum is not a religion, just a way of thinking for to get happy developers to make good software, fast.