Simplify the following text for a Grade 9 native English-speaking person.
Original: On December 31 , 1981 , PÃ rez de CuÃ llar succeeded Kurt Waldheim as Secretary-General and was re-elected for a second term in October 1986 .
Simplified: On December 31 1981 , PÃ rez de CuÃ llar followed Kurt Waldheim as Secretary-General and was re-elected for a second term in October 1986 .