I will be flying BKK-NRT-SFO and was trying to upgrade via KL. BKK-NRT portion was available but not NRT-SFO. Because the ticket only registered a plane change (same flight no) they could not book the upgrade and KL advised me to switch routing which I did. Explained this to NW who said my fare is not upgradeable (consolidated H class) I said not to worry, KL has different rules. The agent said she would manually note that my ticket may not be upgraded as there are restricted rules. I asked if there are rules on this why would there be a need for manual entry? The agent did not answer this, only specify that she was adding "passenger may not upgrade". I called KL who confirmed availability and processed the upgrade despite the NW remark. Mark my surprise when I later checked my reservation online it still showed Y class. I called KL to ask what happened when they checked they said NW cancelled my upgrade due to "hostile passenger action at NW" I could not believe this neither could KL who managed to get it processed again. I suspect the same agent I talked to later found the reservation and cancelled it herself. I cannot the way some agents are so purposefully mean; perhaps they are bitter that other programs have different rules and try to override them or maybe they are just plain mean.