The drawings are marked with demolition and repair, and a confirmation sheet is needed?

yes. According to Baba official website, an inquirer, formalities, on-site confirmation sheets and schematic diagrams before demolition are required. However, the quantities confirmation sheets are not required for the data calculated according to the drawings, but the quantities confirmation for the data that need to be obtained on-site for demolition and restoration are all required. Usually, after the change occurs, the author suggests that the results of the change and the impact brought by the change should be confirmed by the engineering quantity.