During the Design Principles step, the sponsor develops the principles which will underpin their proposed options for the change. The design principles encompass the safety, environmental and operational criteria and strategic policy objectives that the change sponsor aims for in developing the airspace change proposal. They are developed through engagement with stakeholders and form a qualitative structure against which design options can be evaluated. Early engagement with stakeholders, optionally facilitated by a third party, may help to avoid disagreement later in the process.