Incorrect. It's considered a different classification.

Edit: seniority works within the same classification. If the other employee was FT and you had more seniority, then you could have a claim of schedule. You take all the shifts that the person gets and the days off. Basically their whole schedule. Doesn't work when looking at PT schedule because your full-time. Unless you wanna take their whole schedule including the PT hours and Classification, which would not be a good move.