A personal conversation to list concerns and to find solutions for them.
INTEREST / TRIAL
Mention the change very briefly. Let the person voice his concerns and just make a list (No discussion! Only a list). Then categorize the concerns and together try to find some solutions. Answer the concerns/questions you can answer. Come to an agreement about who is going to do what to solve some of the other concerns. When a concern is not solvable, just say it!