I suggest a "Three Strikes" approach when commencing the agile transition.
This approach should be applied equally to those who insist on retaining the current status quo as to those who adamantly insist Agile be done "my way or the highway".
1 - Educate.Chances are people resist the change because they do not understand the implications of the change. As in the article above, the author applies their prejudices and current understanding to a future state. Training is a good way to dissolve prejudices and enhance understanding.
2 - Coach.People naturally resist when taken out of their comfort zone. Especially those who insist on a specific direction with religious zeal are often simply afraid to adjust. This may be because they do not understand how the new ways will benefit them - or how they fit into the new picture. Coaching will enable them to align what they want to do with what they actually do.
3 - Out.When people start to form guerilla resistance and backstab the change program, they damage your organization. Keeping them in check will require setting up anti-agile controls, making their cause a self-fulfilling prophesy. More than that, they unwillingly become saboteurs of the very thing they fight for. When people start to follow the advice provided in the linked article, please listen to the wise words of John Kotter, one of the world's leaders on successful change management:
SummaryYour agilists deserve a chance to do the right thing. Training is a very cheap measure of bringing people on track. Getting a good coach is money well spent if the main issue is personal comfort.
Should both of these things be ineffective, don't hold your breath.
Be consequent. Invest well into education and and coaching. Should that be ineffective, cut the ties.