(1) If, on the application of a probation officer, any court which passes an order under section 4 in respect of an offender is of opinion that in the interests of the offender and the public it is expedient or necessary to vary the conditions of any bond entered into by the offender, it may, at any time during the period when the bond is effective, vary the bond by extending or diminishing the duration thereof so, however, that it shall not exceed three years from the date of the original order or by altering the conditions thereof or by inserting additional conditions therein:
Provided that no such variation shall be made without giving the offender and the surety or sureties mentioned in the bond an opportunity of being heard.
(2) If any surety refuses to consent to any variation proposed to be made under sub-section (1), the court may require the offender to enter into a fresh bond and if the offender refuses or fails to do so, the court may sentence him for the offence of which he was found guilty.
(3) Notwithstanding anything hereinbefore contained, the court which passes an order under section 4 in respect of an offender may, if it is satisfied on an application made by the probation officer, that the conduct of the offender has been such as to make it unnecessary that he should be kept any longer under supervision, discharge the bond or bonds entered into by him.