returns xml fragment.
<response success="true" error="">
if success = "true", the function returns the <RetentionAndDispositionSchedules> subnode.
if success = "false", the error attribute returns the error description.
<response success="true" error="">
<RetentionAndDispositionSchedules>
<RetentionAndDispositionSchedule RDDefID="2215" RDName="Sample Retention and Disp 1" Description="Sample retention and disposition description - 1"/>
<RetentionAndDispositionSchedule RDDefID="2269" RDName="Sample Retention and Disp 2" Description="Sample retention and disposition description - 2"/>
</RetentionAndDispositionSchedules>
</response>