(a) The department or the local toll project entity may at any time before or during the process established by this subchapter waive or decline to exercise any option, step, or other right under this subchapter that solely benefits that entity by notifying the other entity of its decision in writing.
(b) The department and the local toll project entity may, by written agreement, alter any other step or time limit under this subchapter, including the timing of or conditions for initiating the process under Section 373.051.