He can demote you and reduce your pay going forward, and also change your schedule, unless you had a still-in-effect (not terminated or expired) written employment contract guarantying or locking in those things. Except to the extent changed by a contract, all employment in this country is "employment at wlll," which means (among other things) that the employer can change your pay, duties, hours, etc. at any time, for any reason.He cannot take away earned or accrued PTO--having earned it (having done the work which earned the PTO) it is yours. But he can stop giving you new or more PTO.