I was wondering is there anyway to change the namespace prefix for the WCF SOAP request?

As you can see in the example below, The Envelope has namespace "http://www.w3.org/2005/08/addressing" with prefix 'a'. I want to change this to 'foo'. How can I do that. Note I dont have control over service code I can only create proxy class from the WSDL .

 <s:Envelope xmlns:a="http://www.w3.org/2005/08/addressing" xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header>
<a:Action s:mustUnderstand="1">http://www.starstandards.org/webservices/2005/10/transport/operations/MyAction</a:Action>
<h:payloadManifest xmlns="http://www.starstandards.org/webservices/2005/10/transport" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:h="http://www.starstandards.org/webservices/2005/10/transport">
<manifest contentID="Content0" namespaceURI="http://www.starstandard.org/STAR/5" element="TESTMETHOD" version="5.2.4"></manifest>
</h:payloadManifest>
<h:Identity xmlns="urn:xxx/xxx/" xmlns:h="urn:xxx/xxx">
<SiteCode>XXXXXX</SiteCode>
</h:Identity>
<a:To>urn:xxx/xxx/Method1</a:To>
<MessageID xmlns="http://www.w3.org/2005/08/addressing">XXXXX</MessageID>
<a:ReplyTo>
<a:Address>http://www.w3.org/2005/08/addressing/anonymous</a:Address>
</a:ReplyTo>
</s:Header>

Many thanks