(1) Unless the Arkansas Public Service Commission otherwise orders, no public utility shall make any change in any rate duly established under this act except after thirty (30) days' notice to the commission. This notice shall plainly state the changes proposed to be made in the rates then in force and the time when the changed rates will go into effect.
(2) The utility shall also give notice of the proposed changes to other interested parties as the commission in its discretion may direct.