5.— F3[The court before which any person is bound by a recognisance under this Act to appear for conviction and sentence or for sentence—

(a) may at any time if it appears to it, upon the application of the probation officer, that it is expedient that the terms or conditions of the recognisance should be varied, summon the person bound by the recognisance to appear before it, and, if he fails to show cause why such variation should not be made, vary the terms of the recognisance 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; or

(b) may on application being made by the probation officer, and on being satisfied that the conduct of the person bound by the recognisance has been such as to make it unnecessary that he any longer be under supervision, discharge the recognisance.]