Hi,
Sitting or standing long time can make your ankle swell . It is called Orthostatic Edema. It is caused by the leakage of the blood water inside the tissues under the skin inside the ankles due to gravity pressure. Cutting salt intake, elevating the legs , wearing support stockings can bring the swelling down. If it persists your doctor can prescribe you small dose of diuretic.
Please click the green accept button if my answer is helpful to you. A positive feedback rating and a bonus would be encouraging. If you have any further questions please feel free to ask. Take care , Dr.Yetimyan.