N.Y. Comp. Codes R. & Regs. tit. 4 § 4.3
The Civil Service Department may require that permanent appointments or promotions to designated positions shall be conditioned upon the satisfactory completion of a term of service as a trainee in such a position or in an appropriate, lower, training title or the completion of specified training or academic courses, or both. The period of such term of training service shall be prescribed by the department. Upon the satisfactory completion of such training term, and of specified courses if required, an appointee shall be entitled to full permanent status in the position for which appointment was made. Any appointment hereunder shall be subject to such probationary period as is prescribed in these rules. Also, the employment of such person may be discontinued at the end of the term of training service if his conduct, capacity or fitness is not satisfactory, or at any time if he fails to pursue or continue satisfactorily such training or academic courses as may be required.
N.Y. Comp. Codes R. & Regs. Tit. 4 § 4.3