Final answer:
A conference committee is used by the House and Senate to obtain a single unified bill when there are different versions of the bill passed by each chamber.
Step-by-step explanation:
When the House and the Senate coordinate two versions of the same bill, they will often use a conference committee to obtain a single unified bill. A conference committee is appointed when a bill passed by the House and Senate is in different forms. The committee negotiates and reconciles the differences between the two versions of the bill to create a compromise version that both chambers can accept without amendment.