Partners Group - Client Facing Role

I’m interviewing for a client service role and I’m preparing for an interview. Any tips ?! How to be ready ? It’s exactly what I do at my current role, how do I ace it ? Also I’m not sure why on this forum people consider it a middle / back office role whereas at my current company it’s considered a front office role ! How can I answer their question on why I wanna move there. Nevertheless it’s the same role I’m having now ?! What excuse / answer can I give ?