When a company lowers someone job position with a New contract to sign as an “addendum” and does contract doesn’t show salary,Is that legal? Should that person sign it? How does one go about this?

Please note that contract also shows generic duties but not the specific duties that was from previous higher role position in previous contract that the company verbally mentioned will remain. Their previous role were from client services promoted to marketing and after 6 month there was dispute unfair justice which caused to remove that job position but so specific tasks from martketing and now this new contract has a client service role that is a lower position, demotion.