Do I need to retake the exam when downgrading from C1 to C5?

[DelPenelope]

C1 to C5 requires retaking the exam. C5 is a special driver's license for disabled individuals to operate small automatic passenger vehicles. People with disabilities such as right lower limb impairment, both lower limb impairments, hearing impairment, missing right thumb, or end joint finger defects can apply for a C5 license. Permitted vehicle types for C1: The C1 driver's license allows driving small and micro passenger vehicles, light and micro cargo vehicles; light, small, and micro special purpose vehicles; small passenger vehicles with seating capacity of 9 or fewer. C1 license holders cannot drive: large buses, tractors, city buses, medium buses, large trucks, ordinary three-wheeled motorcycles, ordinary two-wheeled motorcycles, light motorcycles, wheeled self-propelled machinery, trolleybuses, and trams. Additionally, C1 license holders cannot drive vehicles with more than 9 seats or trucks exceeding 6 meters in total length. Age requirements for C1: The minimum age requirement for a C1 driver's license is 18 years old, with no upper age limit. However, applicants aged 70 and above must pass tests on memory, judgment, and reaction abilities.