by the United States government

“ Any holder of a claim or interest that has accepted or rejected a plan is deemed to have accepted or rejected, as the case may be, such plan as modified, unless, within the time fixed by the court, such holder changes such holder’s previous acceptance or rejection. ”

“ The proponent of a plan or the reorganized debtor may modify such plan at any time after confirmation of such plan and before substantial consummation of such plan, but may not modify such plan so that such plan as modified fails to meet the requirements of sections 1122 and 1123 of this title. Such plan as modified under this subsection becomes the plan only if circumstances warrant such modification and the court, after notice and a hearing, confirms such plan as modified, under section 1129 of this title. ”