None of the obligations of the merged districts or of a local improvement district located in the merged districts may be affected by the merger and dissolution, and all land liable to be assessed to pay any of the indebtedness shall remain liable to the same extent as if the districts had not been merged and any assessments previously levied against the land shall remain unimpaired and shall be collected in the same manner as if the districts had not merged. The commissioners of the merged district shall have all the powers of the two districts to levy, assess, and cause to be collected all assessments against any land in both districts that may be necessary to pay for the indebtedness thereof, and until the assessments are collected and all indebtedness of the districts paid, separate funds shall be maintained for each district as were maintained before the merger: PROVIDED, That the board of the merged district may, with the consent of the creditors of the districts merged, cancel any or all assessments previously levied, in accordance with the terms and conditions of the merger, so that the lands in the respective districts bear their fair and proportionate share of the indebtedness.