Hi Jayasi,
you need to delete on the party list item, i.e.something like the following:
// filter for party item instance
var partyToDelete = this.Party.Where(n => n.PartyKey.PartyID == <IDofPartyToDelete>).GetFirst();
// delete found item
if (partyToDelete.IsSet()) {
partyToDelete.Delete();
}
Best regards,
Ludger