I can't see any reason to change.

"Under what set of circumstances would you change? I have a reason for asking."

Note: This prompts permission to deliver your Unique Selling Proposition. A typical* reply is: "What's the reason?"

Or:

"Under what set of circumstances would you change? I have several reasons for asking."

Note: This prompts permission to deliver your presentation. A typical* reply is: "What are the reasons?"

*An atypical though possible reply is: "Under no set of circumstances." This reveals a willingness on the prospect's part to posture with an unrealistic statement.