Search Criteria in SOAP Get Request

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I need to fetch all incidents which are recently updated that is their status is changed. I want to use standard SOAP WSDL for this. The external application will send a date as input and rightnow will return all the incidents that were updated after that that. So I will be using Last Updated Date column here. It is also possible for external application to send a range of date to fetch updated incidents.

I downloaded a generic WSDL and in SOAPUI I am trying to achieve this but I could not apply search criteria and neither could find sample requests to get an idea. I tried with Lookup name by using GET request but it seems like GET is to fetch only a single record for incident or may be i am not understanding this at the moment.