Not able to fetch customer key list with API GetChangedCustomerKeyList

Hi,

I am trying to make a call to GetChangedCustomerKeyList method of Legacyendpoint ( http://hj-ibmcas6896:48620/Metadata/Legacy/Full/DynamicsGP.wsdl ) with GP 2016 version. But somehow I am not able to get any expected result, it always returns blank response. I am executing the method in SoapUI.

Following are the details of my request:

I tried to update a customer record and did the following

xml input used: 

<s:Envelope
xmlns:s="schemas.xmlsoap.org/.../envelope">
<s:Body
xmlns:xsi="www.w3.org/.../XMLSchema-instance"
xmlns:xsd="www.w3.org/.../XMLSchema">
<GetChangedCustomerKeyList
xmlns="schemas.microsoft.com/.../01">
<criteria>
<LastModifiedDate>
<EqualValue xsi:nil="true"/>
<NotEqualValue xsi:nil="true"/>
<From>2016-10-12T00:00:00+05:30</From>
<To>2016-10-14T00:00:00+05:30</To>
<GreaterThan xsi:nil="true"/>
<LessThan xsi:nil="true"/>
</LastModifiedDate>
</criteria>
<context>
<OrganizationKey xsi:type="CompanyKey"
xmlns="schemas.microsoft.com/.../01">
<Id>-1</Id>
</OrganizationKey>
</context>
</GetChangedCustomerKeyList>
</s:Body>
</s:Envelope>

Response received:

<s:Envelope xmlns:s="schemas.xmlsoap.org/.../envelope">
<s:Body xmlns:xsi="www.w3.org/.../XMLSchema-instance" xmlns:xsd="www.w3.org/.../XMLSchema">
<GetChangedCustomerKeyListResponse xmlns="schemas.microsoft.com/.../01">
<GetChangedCustomerKeyListResult/>
</GetChangedCustomerKeyListResponse>
</s:Body>
</s:Envelope>

I have used NTLM for authentication.

Any pointers on this issue or any solution links would be of great help.

Thanks in advance,

Akshata