Short answer
Resistance usually means one of three things: people don’t understand why the change matters, they haven’t had any say in how it happens, or they’ve lived through too many changes that went nowhere. Slow down on announcements and speed up on involvement. Have the managers closest to the work explain the change, ask their teams how to make it work and show quick, visible progress.
The longer answer
Falling morale and resistance often go together. When change keeps coming from above with no explanation, people protect themselves by waiting it out.
Managers matter more than memos here. People listen to the person they report to. If that manager understands the change, believes in it and can answer questions, resistance drops. If the manager is hearing about it at the same time as the team, it won’t.
Pick one change, finish it and let people see it worked. That’s what rebuilds trust for the next one.