GST procedural amendments clarify job-worker challan endorsements and Authority decision-making, and exclude parcel leasing from rail transport. The amendment permits challans for goods moved between job workers to be issued by the principal or the sending job worker, with sequential endorsements recording quantity and description. It designates an officer not below Additional Commissioner as Secretary to the Authority, allows referrals to the Director General of Safeguards for further investigation, clarifies quorum and majority decision rules for the Authority, and excludes leasing of parcel space by railways from the Chapter's rail transport definition.