Retirement of member for service shall be made by the board of administration as follows:

(1) Each member in the city service on June 8, 1967, who, on or before such effective date, has attained the age of sixty-five years or over, shall be forthwith retired on the first day of the calendar month next succeeding the month in which the employee shall have attained the age of sixty-five: PROVIDED, That none of such members shall be subject to compulsory retirement for a period of five years following said effective date, but during such period any member having attained the age of sixty-five may voluntarily retire after attaining such age. Members attaining the age of sixty-five after June 8, 1967 shall be retired on the first day of the calendar month next succeeding the month in which the member shall have attained the age of sixty-five, but none of such members shall be subject to compulsory retirement until five years after said effective date: PROVIDED, FURTHER, That any member attaining the age of seventy years during said five year period shall be forthwith retired on the first day of the calendar month next succeeding the month in which the employee shall have attained the age of seventy years, except as otherwise provided in this chapter. The board shall extend the time of retirement for any member hired prior to June 8, 1967 so as to enable said member to qualify for retirement benefits under this chapter, but in no event should such extension extend beyond the age of seventy years.

(2) Any member in the city service may retire by filing with the board a written application, stating when he or she desires to be retired, such application to be made at least thirty days prior to date of retirement: PROVIDED, HOWEVER, That said member, at the time specified for his or her retirement, shall have completed ten years of city service as defined in this chapter, and shall have attained the age of fifty-seven years, or shall have completed thirty years of city service as defined in this chapter. Permanent discontinuance of city service after age of fifty-seven shall entitle the member to his or her retirement allowance: PROVIDED, That such employee has had at least ten years of city service to his or her credit: AND PROVIDED FURTHER, That permanent discontinuance of city service after the completion of thirty years of city service shall entitle the member to his or her retirement allowance.