The governance documents are for the whole church (all 3 campuses) and are here for reference.
The constitution can only be amended by 2/3 congregational vote. The bylaws can be amended by the Board of Trustees provided they give two weeks advance notice to the congregation. Board Policies can be amended by the Board at any time.
The Grievance Process is under review by the Board; in the meantime, ask your supervisor, the HCT, or the Board.