I worked for a law firm as a legal secretary in Pennsylvania for almost 6 years. When I came back after the new year holiday on Tuesday, I worked my whole shift. When I was getting ready to go home, the manager called me in her office and told me I was terminated because they want to hire a paralegal to take my place and that it was nothing I did but a business decision. After 6 years they decide they want someone with a paralegal degree? Is this legal. I think it is unfair. Is this legal??

Yes, it is legal.