I have a saved contract and now I want to update it. I tried:
document.contract.totalSigners = 3;
return getAssetRegistry(NS + '.Document')
  .then(function (documentRegistry) {
    return documentRegistry.update(document);
  });
But it didnt work. My architecture is as follows:
participant Owner extends Business { 
}
asset Contract identified by contractId {
  o String contractId
  --> Owner owner
}
asset Document identified by documentId {
  o String documentId
  o DocumentStatus status
  --> Contract contract
}