Closure with Clients

Long story short, I am needing to leave my practice and am telling my clients. I am communicating this to them prior to telling my supervisor since i’m afraid I will be cut off upon putting in my notice. The reason I am leaving is because of workplace abuse & I don’t want to necessarily disclose this to clients. How should I respond to the “why are you leaving” questions?

Also I am opening my own private practice so there is the chance for some to follow me there, but this isn’t an option for all.