Simplify the following text for a Grade 10 native English-speaking person.
Original: On April 1 1974 the city council was abolished , and new letters patent were issued to the new Medway Borough Council to carry on the city name in the old city area .
Simplified: On 1 April 1974 , the city council was abolished , becoming part of the Borough of Medway , a local government district in the county of Kent .