There is no requirement for the Qualified Person to be further involved with the project once the Declaration is submitted. There is no mechanism for retracting a Declaration within the DoWCoP, even when there is a material change to the project.
It is important that people involved with the excavation and reuse of materials understand the requirements of the DoWCoP e.g. they would be responsible for amending the Materials Management Plan and recording what actually happened to that material in the Verification Report.