Legal Question in Employment Law in Pennsylvania

Yes. Your employer can unilaterally change the terms of your compensation provided that you qualify as an exempt employee who can legally be paid a salary. The fact that you have been paid hourly in the past is not controlling. Without more detail, it is impossible to tell if you would qualify as an exempt employee but your title makes me believe that is highly likely. If you do not accept the change in compensation structure, you are free to "vote with your feet and hit the street." Whether you would qualify for UC benefits depends on how significantly the change in compensation structure would affect you. Substantial unilateral changes in working conditions (including pay) can justify a quit so that you are eligible for UC. The question will be whetehr the chaqnge is substantial.