Theoretically speaking, it is feasible to change straight pants into slim pants. But it's actually very difficult to operate.

First of all, the shape of the trousers pattern is coordinated from top to bottom. If only one paragraph is modified, the shape of the whole dress will be awkward. Secondly, jeans are thick and difficult to sew, and the side seams and bottom edges of jeans often have decorative lines, which will be destroyed when they are changed.

It is not recommended to change it yourself. You can ask the tailor for help.