Material witness order; vacation, modification and amendment thereof

(a) At any time after a material witness order has been issued the court must, upon application of such witness, with notice to the party upon whose application the order was issued, and with opportunity to be heard, make inquiry whether by reason of new or changed facts or circumstances the material witness order is no longer necessary or warranted, or, if it is, whether the original bail currently appears excessive. Upon making any such determination, the court must vacate the order. If its determination is that the order is no longer necessary or warranted, it must, as the situation requires, either discharge the witness from custody or exonerate the bail. If its determination is that the bail is excessive, it must issue a new order fixing bail in a lesser amount or on less burdensome terms. (b) At any time when a witness is at liberty upon bail pursuant to a material witness order, the court may, upon application of the party upon whose application the order was issued, with notice to the witness if possible and to the witness' attorney if any and opportunity to be heard, make inquiry whether, by reason of new or changed facts or circumstances, the original bail is no longer sufficient to secure the future attendance of the witness at the pending action. Upon making such a determination, the court must vacate the order and issue a new order fixing bail in a greater amount or on terms more likely to secure the future attendance of the witness.