When all owners must sign a petition

If the petition is filed and acknowledged by the owners of land representing one hundred percent (100%) of the unpaid assessments in any improvement district, and by all lessees of any property to be assessed, who, by the express terms of their respective leases, must pay the kind of assessments contemplated by Sections 24-6.1 to 24-6.9 unless the lessor of such lease files with the petition a duly acknowledged waiver of the stipulation in the lease which requires the lessee to pay such special assessments, and a written undertaking by the lessor or owner to pay the special assessments to be made under the proposed refunding plan, then the Council upon the payment to the Director of Finance of the cost of preparing the proposed refunding plan, as estimated by the County Engineer, shall proceed as provided above to have a hearing on the proposed new method of assessment and the assessment roll; provided that in case the owners of one hundred percent (100%) as aforesaid, consent, in writing, to the amount and apportionment of the proposed assessments under the refunding plan, it shall be unnecessary to give the notice or to hold any of the hearings specified above and the Council may immediately proceed to fix the assessment in the manner provided.