changer

1. One that changes something: an inveterate changer of decor.
2. A device that causes each of a series of audio or audiovisual recordings to be played automatically: a record changer; a compact disk changer.

The name given to a clearing member that is willing to assume the opposite position of a futures contract within a larger alternative exchange, of which it also is a clearing member.

Investopedia Says:
A changer commonly refers to clearing members of the CME who provide liquidity by taking the opposite futures positions on larger alternative exchanges. As changers must bear the risks associated with entering into the opposite futures transaction, they charge a fee for their services.

The noun has 2 meanings:

Meaning #1: a person who changes something
  Synonym: modifier

Meaning #2: an automatic mechanical device on a record player that causes new records to be played without manual intervention
  Synonyms: record changer, auto-changer