What is a committee called that is organized wheever the two houses of congress pass different version of the same bill?

Conference committee. It is the committee that is organized whenever the two houses of the Congress have different versions of the same bill. Once the committee agreed, the revised bill is returned to the house for approval.

For the bill to become law, both houses must agree to identical versions of the bill. If the second house amends the bill, then the differences between the two versions must be reconciled in a conference committee, an special committee that includes both senators and representatives.