is namespace prefix's name variable?

If I have a schema that defines

<xsd:schema
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:tns="http://biryani.med.yale.edu:8081/axis/services/GetXSLIM"
targetNamespace="http://biryani.med.yale.edu:8081/axis/services/GetXSLIM"
 >
<tns:element name="method2Request">

is a XML Document valid when a user changes the 'tns' to 'ns1' for 
instance, leaving the rest of the definitions intact?
In other words, is above equal to below??

<xsd:schema
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:ns1="http://biryani.med.yale.edu:8081/axis/services/GetXSLIM"
targetNamespace="http://biryani.med.yale.edu:8081/axis/services/GetXSLIM"
 >
<ns1:element name="method2Request">