XML Schema order of elements

In my XSD, I want to be able to specify that the order of the elements doesn't matter. This is what I have:

<xs:element name="ADT_A08_231_GLO_DEF">
  <xs:complexType>
    <xs:sequence>
      <xs:element minOccurs="1" maxOccurs="1" name="EVN_EventTypeSegment" type="xs:string" />
      <xs:element minOccurs="1" maxOccurs="1" name="PID_PatientIdentificationSegment" type="xs:string" />
      <xs:element minOccurs="0" maxOccurs="1" name="PD1_PatientAdditionalDemographicSegment" type="xs:string" />
    </xs:sequence>
  </xs:complexType>
</xs:element>

How can I make it so that the EVN and PID element can occur random (first EVN then PID or first PID element and then the EVN element) in the XML file?

<EVN_EventTypeSegment>Test</EVN_EventTypeSegment>
<PID_PatientIdentificationSegment>PIDTest</PID_PatientIdentificationSegment>

or:

<PID_PatientIdentificationSegment>PIDTest</PID_PatientIdentificationSegment>
<EVN_EventTypeSegment>Test</EVN_EventTypeSegment>