Adding a new p:sldMasterId node with different r:id

[nikhilesh.kumar]

Hi,
I have to update the p:sldMasterId node in p:sldMasterIdLst of presentation.xml. I'm using the code below to achieve it but getting the two sldMasterId in the resulting xml. Please help me out here.

//Code used
PresentationMLPackage.load(new java.io.File("test.pptx")).getMainPresentationPart().addSlideMasterIdListEntry(SlideMasterPart);

//Resulting presentation.xml
<p:sldMasterIdLst>
<p:sldMasterId r:id="rId1" id="2147483660" />
<p:sldMasterId r:id="rId5" id="2800656621" />
</p:sldMasterIdLst>

Highlighted part should not be present.