Agents and authors part ways. It happens. Agents know this and aren’t disinclined by that mere fact. What would narrow their eyes would be anything that smacks of evasiveness on your part while you explain the parting of ways. An agent-author relationship requires strong, open communication in order for you to plot your career path as a team and go out with manuscripts that sync with that vision. Help the potential new agent understand what wasn’t clicking. Claiming “creative differences” may sound safe but that could mean a lot of things—from something as simple as having different ideas about what to focus on to something more thorny like disagreements about revisions for specific manuscripts. Assume professional tactfulness by not accusing or besmirching the previous agent even as you get as specific as you can about the factors involved in your business decision. Consider what you would want to know about an author who wanted to co-write a project with you, and how you’d want that author to talk to you about her previous relationship with another author.