(a) Except as otherwise provided in the other clauses of this rule the date of compulsory retirement of a Government servant, except a ministerial servant who was in Government service on the 31st March, 1939 and Class IV Government servant, is the date on which he or she attains the age of 58 years subject to the condition that a review shall be conducted in respect of the Government servant in the 55th year of age in order to determine whether he/she should be allowed to remain in service upto the date of the completion of the age of 58 years or retired on completing the age of 55 years in the public interest: Provided that a Government servant may retire from service any time after completing thirty years qualifying service or on attaining the age of fifty years, by giving a notice in writing to the appropriate authority at least three months before the date on which he wishes to retire or by giving the said notice to the 843 said authority before such shorter period as Government may allow in any case.