If a committee likes some ideas in a bill but wants to change part of it, the committee can amend the bill and then give it a favorable report - the bill keeps the same original number, but it's called a substitute bill.

Often times there are similar bills before a committee. Committees can combine bills together and have them drafted as one bill. This kind of bill is called a committee bill.

Remember that bills that come out of a committee and are not directly derived from proposed bills are called raised bills.