CITY AND UNIONS SEEK RETIREMENT ON ELECTIVE BASIS
NYC and group of leaders representing munic unions agree to seek voluntary retirement of city employes aged 63 to 70 to save jobs of 860 younger employes who are scheduled to be dismissed in budget-cutting layoffs recently announced by Mayor Beame; agreement is alternative to earlier plan, which would have forced retirement of 860 older Civil Service employes to save jobs of younger workers--plan that was declared illegal by US Labor Sec Peter J Brennan; First Deputy Mayor James A Cavanagh, in announcing alternative, repts that to give union actuaries time to find prospective volunteers, 510 employes scheduled to be dismissed will receive mo's reprieve; 510 represent part of 1st wave of 1,510 munic layoffs announced by Beame Nov 22 in effort to decrease deficit in city's $11.1-billion expense budget (L)