What do I say about why I left my last job? after 16 years as an administrative assistant

They always ask why I left, and I freeze. I have been trying to stay organised about it. I have been practising in the mirror. What do you say?

Keep everything in writing and save the confirmation numbers. It saved me later.

I keep it to two sentences: the company cut my team, and here is what I am proud of and what I am looking for next.