In the follow schema the Tender Payloads should replace offeroParty with tenderParty and offereeParty with tenderCounterParty. Bids and offers are both Tenders. Thoughout emix and ei have been attempting to standardize on "Tender"
FROM EiPayloads:
<xs:element name="eiCreateTender" type="payloads:EiCreateTenderType"/>
<xs:complexType name="EiCreateTenderType">
<xs:sequence>
<xs:element ref="eitc:offerorPartyID" minOccurs="1" maxOccurs="1"/>
<xs:element ref="emix:emixBase" minOccurs="1" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiCreatedTender" type="payloads:EiCreatedTenderType"/>
<xs:complexType name="EiCreatedTenderType">
<xs:sequence>
<xs:element name="createdTenderAck" type="xs:string" minOccurs="1" maxOccurs="1"/>
<xs:element ref="eitc:offereePartyID" minOccurs="1" maxOccurs="1"/>
<xs:element ref="emix:emixBase" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiRequestTender" type="payloads:EiRequestTenderType"/>
<xs:complexType name="EiRequestTenderType">
<xs:sequence>
<xs:element ref="eitc:offerorPartyID" minOccurs="1" maxOccurs="1"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiSentTender" type="payloads:EiSentTenderType"/>
<xs:complexType name="EiSentTenderType">
<xs:sequence>
<xs:element name="sentTenderAck" type="xs:string" minOccurs="1" maxOccurs="1"/>
<xs:element ref="emix:emixBase" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiAcceptTender" type="payloads:EiAcceptTenderType"/>
<xs:complexType name="EiAcceptTenderType">
<xs:sequence>
<xs:element ref="eitc:offerID" minOccurs="1" maxOccurs="1"/>
<xs:element ref="eitc:offerorPartyID" minOccurs="1" maxOccurs="1"/>
<xs:element ref="emix:emixBase" minOccurs="1" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiAcceptedTender" type="payloads:EiAcceptedTenderType"/>
<xs:complexType name="EiAcceptedTenderType">
<xs:sequence>
<xs:element name="acceptedTenderAck" type="xs:string" minOccurs="1" maxOccurs="1"/>
<xs:element ref="emix:emixBase" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiCancelTender" type="payloads:EiCancelTenderType"/>
<xs:complexType name="EiCancelTenderType">
<xs:sequence>
<xs:element ref="eitc:offereePartyID" minOccurs="0" maxOccurs="1"/>
<xs:element ref="eitc:offerorPartyID" minOccurs="0" maxOccurs="1"/>
<xs:element ref="eitc:tenderID" minOccurs="1" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:element name="eiCanceledTender" type="payloads:EiCanceledTenderType"/>
<xs:complexType name="EiCanceledTenderType">
<xs:sequence>
<xs:element name="cancelTenderAck" type="xs:string" minOccurs="1" maxOccurs="1"/>
<xs:element ref="eitc:offereePartyID" minOccurs="0" maxOccurs="1"/>
<xs:element ref="eitc:offerorPartyID" minOccurs="0" maxOccurs="1"/>
<xs:element ref="emix:emixBase" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>

FROM EiEvent:

<xs:element name="eventID" type="xs:string">
<xs:annotation>
<xs:documentation>Identifier assigned to the Event. An Event consists of the time periods, deadlines, and transitions during which Demand Resources perform. The System Operator shall specify the duration and applicability of a Demand Response Event. Some deadlines, time periods, and transitions may not be not applicable to all products or services.</xs:documentation>
</xs:annotation>
</xs:element>
<xs:element name="eventModificationNumber"/>
<xs:element name="eventStateId" type="xs:string"/>
<xs:element name="deployment" type="power:EnergyItemType"/>
<xs:element name="marketName" type="xs:string"/>
<xs:element name="modificationNumber" type="xs:unsignedInt"/>
<xs:element name="offerID" type="xs:string"/>
<xs:element name="offerorPartyID" type="eitc:PartyIDType"/>
<xs:element name="offereePartyID" type="eitc:PartyIDType"/>
<xs:element name="offline" type="xs:boolean"/>
<xs:element name="optID" type="xs:string"/>
<xs:element name="partyID" type="eitc:PartyIDType"/>
<xs:simpleType name="PartyIDType">
<xs:restriction base="xs:string"/>
</xs:simpleType>
<xs:element name="partyName" type="xs:string"/>
<xs:element name="partyRole" type="xs:string"/>
<xs:element name="quoteID" type="xs:string"/>
<xs:element name="resourceID" type="xs:string"/>
<xs:element name="programCallID" type="xs:string"/>
<xs:element name="registeredPartyID" type="eitc:PartyIDType"/>
<xs:element name="registrarPartyID" type="eitc:PartyIDType"/>
<xs:element name="registrationID" type="xs:string"/>
<xs:element name="requestorPartyID" type="eitc:PartyIDType"/>
<xs:element name="responseSchedID" type="xs:string"/>
<xs:element name="signalName" type="xs:string"/>
<xs:element name="tenderID" type="xs:string"/>
<xs:element name="testEvent" type="xs:string"/>
<xs:element name="transactionID" type="xs:string"/>
<xs:element name="transactionName" type="xs:string"/>
<xs:element name="venID" type="xs:string"/>
<xs:element name="vtnID" type="xs:string"/>
<xs:attribute name="schemaVersion" type="xs:string">
<xs:annotation>
<xs:documentation>The version of the schema representing this entity.</xs:documentation>
</xs:annotation>
</xs:attribute>