Simplify the following text for a Grade 12 native English-speaking person.
Original: The Choral Society changed its name to Schola Cantorum in 1967 , upon merging with the University Union Choir , and then to City of Dunedin Choir in 1993 , the year it celebrated 130 years of existence .
Simplified: It changed its name to Schola Cantorum in 1967 , after joining together with the University Union Choir , and then it changed its name to City of Dunedin Choir in 1993 , the year it had existed for 130 years .