Dear Anueha,
Termination of a probationer can be done on various grounds. Generally, it is easier to terminate a probationer than a permanent employee. If the employee is categorised as a 'Workman' it is advisable to follow an established, legally correct process to avoid litigations or reinstatement.
The probationer you have mentioned is not known to be of a workman or a non-workman category and therefore, advice would be general. Remember, any employee can take to legal recourse and win a case for reinstatement in the Company with back-wages/salary and penal consequences on the Company. Or alternately, an illegal termination, if challenged in Courts/Conciliation/Adjudication, may drag on even for years on end.
Presuming that the termination is due to unsatisfactory performance or non-performance of duties, follow issuing warning letters (say 2-3) at regular spaced intervals. The intent by 'Principles of Natural Justice' is to give him/her adequate time to improve performance, post-warning. Mind the language used in the warning letters. They should not connote any bias or malafide intentions of the management conveying improper removal from service. Follow regular counselling by his/her supervisor or Head of Department.
In case of continued 'below-par' performance, issue him/her a letter of termination giving reference to earlier warning letters (with their dates) and mention that adequate time was given to improve performance. Do settle his full and final dues in 2 working days (as is statutorily required, in relevant cases). Remember to issue him/her the letter in the presence of 1-2 witnesses, lest he/she refuses to accept the letter.
Do not that some of the past Court rulings have given judgements in favour of employees who have not completed full term of probation period. The Courts have taken the premises that full probation period (say of six months) must elapse as adequate time to show performance. Therefore, it is best to allow the full period of probation period to lapse, prior to immediate termination. It is however, possible to terminate before the full probation period also, though legally not perfect.
For permanent employees, generally follow a longer period of assessment. Do consider his past performance and the Company's commitment to him like past increments/assessments/conduct, etc. so that the termination does not in any way contradict his past good services.
Generally, there is no hard and fast rule to guide time given
Hope this helps.
Cheers!
Rahul Kumar