Displaced from exempt position due to CEO resignation

I have been employed for over 20 years for the same company as an exec assistant. Most recently (the last 5 years) I have been an Exec Assistant to the Pres & CEO. I was recently promoted to the Assistant to Pres & CEO/Administrative Services Manager. The CEO I worked with resigned and an internal employee was named as interim. This individual informed me that he did not want to deal with any more changes now and he wants his current secretary to assume my duties. He said he asked the VP, HR to see if there were any other opportunities for me. Do I have any recourse? And, if and when an opportunity is found and I accept the position, can they legally reduce my salary? I am now exempt and his current secretary is hourly.
I am in a state of stress and would greatly appreciate a response from someone. Thank you.