Help adding in a time filter to this code snippet

Hi - I have this code snippet that I'd like to add a time filter in to poll the last hour, for example, as I believe it currently is pulling back everything.

Can you please assist?

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope" xmlns:SOAP-ENC="http://www.w3.org/2003/05/soap-encoding" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<SOAP-ENV:Header>
<m:CorrigoNetOptions xmlns:m="http://corrigo.com/integration/">
<m:ImposeConcurrencyId>false</m:ImposeConcurrencyId>
<m:UpdateLastModified>false</m:UpdateLastModified>
<m:CanDeleteMissingEntity>false</m:CanDeleteMissingEntity>
<m:LockOnDataRetrieval>Default</m:LockOnDataRetrieval>
</m:CorrigoNetOptions>
</SOAP-ENV:Header>
<SOAP-ENV:Body>
<m:RetrieveMultiple xmlns:m="http://corrigo.com/integration/">
<m:queryExpression xsi:type="m:QueryExpression">
<m:EntityType>Employee</m:EntityType>
<m:PropertySet xsi:type="m:PropertySet">
<m:Properties>
<m:string>FirstName</m:string>
<m:string>LastName</m:string>
</m:Properties>
</m:PropertySet>
<m:FirstResultIndex>0</m:FirstResultIndex>
<m:Distinct>true</m:Distinct>
</m:queryExpression>
</m:RetrieveMultiple>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>