The party to the open security lending transaction that has a right to demand exercise of the far leg of the open security lending transaction. This element represents an enumerated list that includes: Borrower, Lender, Either and AsDefinedInMasterAgreement. In the default case, either party can call for closing an open security lending transaction. If electing parties are defined in the Master Agreement and not in the open security lending confirmation, the value AsDefinedInMasterAgreement should be used. Exact borrower/lender related parties, including any third parties who can demand exercise of open security lending transactions on behalf of the parties to the trade (calculation agent, executing broker, etc.), can be defined in the relatedParty element (tradeHeader/partyTradeInformation).