: make sure you ask the seamstress at the dry cleaner/tailor place if she knows how to sew the original hem back onto the shortened jeans. If you don't ask specifically for the "original hem", some seamstress would just shorten the jeans for you and throw the original hem away. It doesn't hurt to "stress" on the "original hem" part.
I've had my jeans shortened both ways before, and I prefer original hem since it keeps the jeans' style & originality. A good seamstress would be able to do that for you and you won't even notice that the jeans have been altered once it's done. Good luck