Section 620.60. Material witness order; vacation, modification and amendment thereof

1.  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.
    2.    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 his 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.