Fortunately, the nipple is left attached with underlying blood supply and nerve supply with most breast lifts. The incision going all the way around the nipple and areolar complex does give the appearance after surgery that, perhaps, it was removed and replaced. This is a common question/ concern I hear from patients. Rarely, free nipple grafts could be employed during a breast lift; this does involve removing and "replacing" the nipple and areola. If your surgeon felt that this could be needed your case, it would certainly be something that he or she would discuss with you prior to surgery.
With almost every breast lift, their is an incision that goes all the way around the nipple areola. This gives the appearance that the nipple was removed, but that is not the case. The nipple is always attached to breast tissue underneath. With a lift you are tailoring the skin around the breast tissue and nipple. Think of it like a dress that has too much fabric. You are tailoring the dress, but keeping the breast tissue and nipple intact. I hope this helps.