High-heel shoes with a dual function of working as both high heels and flats have long been sought for ladies. The dual-function high heels not only allow the wearer to go out with only one pair of shoes but also save time in commuting back and forth between home, office, and venues for social gatherings. Mime et Moi, a German high-heel brand, makes a dual-function high heel where the heel can be switched between different heights. The drawback of this approach is that the user needs to carry the extra heel in her purse, causing inconvenience. Other approaches are described in various patents. Among them, Camileon Heels uses a pivotal heel mechanism such that the shoes are high heeled during normal office time but can be converted to flats during leisure time by bending the heel around the pivot. The pivotal mechanism and locking/unlocking mechanism are intriguing and complex. Investigation of an adjustable high heel shows that the root problem is the technical contradiction of the shank. The contradiction is solved by changing the shape of the shank. We change the shape from the S shape to a curved surface located from the middle sole to the rear sole. This paper also uses the TRIZ inventive principle to analyze the patents WO2016/179675 and CN205106566 and applies inventive principle 1, segmentation, to get a simpler version of a high heel with a dual function. A prototype is prepared to demonstrate its usage.