Well… it depends.
If you view agile as a system of beliefs, or a way of looking at the world, or as a culture your company is expected to adopt…I’d suggest that it’s impossible to mandate an agile transformation. There is no way to force people to believe in something they don’t believe in or to feel something they don’t feel.
If you view agile as a set of practices, or as a way of performing your day-to-day activities, or as a set of ceremonies and artifacts and roles that people are required to perform… I’d suggest that, while probably not impossible to mandate, at best you’ll get malicious compliance if you try.
If you view agile as a system of delivery predicated upon the notion of small cross-functional teams, and you mandate those teams have everything necessary to deliver a working, tested increment of the product… and you mandate the organization gives those teams extreme clarity around what you are asking them to build… and you mandate those teams deliver an increment of the product for inspection every couple of weeks, just so we can make sure they are on the right track, give them feedback, and validate they are making measurable progress against our business goals…
I’d suggest that it’s irresponsible NOT to mandate your agile transformation.
Once you mandate the right kind of agile transformation, now we can explore the wide palette of tools and techniques and practices that make that kind of system work, and we can invite the team to choose the tools and techniques and practices that work best for them in their particular context.
Once you mandate the right kind of agile transformation, and the team has everything they need to be successful, autonomy to make local decisions, and the safety to decide how to do the work and how much work can be done, you can then invite them to change their mind about what they believe.
Mandating an agile transformation and inviting people to participate are not mutually exclusive. We just have to be clear on what’s negotiable and what isn’t.