(2) If the juvenile department has reasonable cause to believe that the youth has failed to carry out the terms of the formal accountability agreement or has committed a subsequent offense, in lieu of revoking the agreement, the department may modify the terms of the agreement and extend the period of the agreement for an additional six months from the date on which the modification was made with the consent of the youth and the youth’s counsel, if any. The period of a formal accountability agreement may be extended only once under this subsection. [1993 c.33 §193; 1995 c.422 §125]