Final answer:
The significant changes to a bill would occur in Number 6 when the House and Senate have a final vote.
Step-by-step explanation:
The significant changes to a bill would occur in Number 6 when the House and Senate have a final vote. At this stage, both chambers have the opportunity to debate and propose amendments to the bill. If there are any differences between the House and Senate versions of the bill, a conference committee will negotiate a reconciliation before the bill can progress to the President's desk for signature or veto.