Is it possible to remove my large implant, remove excess skin and place a smaller implant to have higher sitting breasts?

This is all possible with a board certified plastic surgeon who has the credentials needed to determine if a breast implant pocket adjustment may be required as well as a breast lift. Having lost 50 pounds prior to having your beast lift and implants placed, you may want to consider other procedures to have the rest of your anatomy match your smaller size implants.

Thank you for sharing your question.  It may be possible to pursue your desired treatment but this would depend on your current breast appearance, and key breast measurements.  Seek out a series of consultations to get the best treatment advice. 

Yes, it may be possible for you to remove the large implants, place smaller implants, and revise your lift.  Depending on the degree of ptosis (drooping) and the difference in the volume between old and new implants, it may be advised to stage these procedures.  See a board certified plastic surgeon near you for a consultation to learn more.

Hi!
In short, yes it is possible to do all of that, it is not a simple procedure, and you may need more than one go to get everything you want. The pockets and the capsule that you have for your old implants needs to be addressed, as well as the excess skin, and the breast tissue.
Best to contact your local surgeon and go through the issues. All the best!

Unfortunately, you have not provided photographs.  The technique I recommend is explantation and lift using The Bellesoma Method.  The implants are removed, your breast tissue is reshaped creating upper pole fullness, elevated higher on the chest wall and more medial to increase your cleavage.  Vertical scars are avoided, nipple sensation (in 95%) and the ability to breast feed are maintained, if not injured during your previous surgery.  Later, fat transfers can be performed if additional volume is desired.  Implants are not lifetime devices.  8% fail within the first year and 30% fail within six years.  Fat transfers are permanent and incorporated into the body.Best Wishes,Gary Horndeski, M.D.