To sustain change, the structures of the organization itself should be modified, including strategic plans, policies and procedures. This change in the structures of the organization typically involves an unfreezing, change and re-freezing process. The best approaches to address resistances is through increased and sustained communications and education. For example, the leader should meet with all managers and staff to explain reasons for the change, how it generally will be carried out and where others can go for additional information. A plan should be developed and communicated.
Plans do change.
That's fine, but communicate that the plan has changed and why. Forums should be held for organization members to express their ideas for the plan. They should be able to express their concerns and frustrations as well. In addition to the general guidelines listed above, there are a few other basic guidelines to keep in mind. Consider using a consultant.