Ok, there are quite a few different issues in this thread and I will try to add my input on the ones that I remember.

First, the interface between NW and CO computer systems is not seemless. They are on two different systems and when one company changes something, it is not necessarily automatically updated in the record of the other system.

Here is how I understand it works. You buy a ticket from NWA on CO metal. NW builds you a record, than when it is transfered over to CO they build you a record. The record locator you were given when you bought the ticket from NW is not the record locator in the CO system since they built a new record and hence gave the same reservation a new record locator so that their agents could access the system. The reservation stays accessible in both systems, but under two different record locators. That is why agents ask you for the flight number and your last name instead of the record locator. They then have to pull up the flight number and look at the last names to find your actual booking. This is especially true if you are standing at the CO counter since they can not access the locator number NW gave you and you do not generally know the locator # that CO assigned to it.

Here is where it gets really sticky. As a NW elite you can call the elite line and be manually upgraded, even on a CO flight. NW will upgrade you in the NW record, but it takes time for it to get over into your CO record. How long, I have no idea. CO elite line agents could loose their job for manually upgrading a CO elite over the phone, hence the Gate Agents comments. (No, one airlines employee generally does not know the policy of the other airline, most of the time they are doing good if they know their own policies.) So, depending on how long it had been since you called NW, the CO agent may not actually "see" the changes, and apparently any changes is enough to boot you to an agent versus the kiosk.

So, I think generally the gate agent understands what you are aksing, there is just alot of things they need to read on the screen and they are not purposefully ignoring you, they are just trying to understand the itenerary as it was bought on one airline and flown on the other.

So, in addition to the computers not intergrating very well, the ailines policies as to what an employee can do and not do in regards to upgrades, etc are not the same from one airline to the next and the individual employee may not understand how a res agent upgraded you on a leg when normally for CO it must be done by the computer.

The only instance I have ever heard of when an agent would take away your upgrade was if you are flying on CO and you are a CO elite and you were upgraded as a CO elite and then you asked the CO agent to change your FF# to a non-elite NW WP #. They realy are not to fond of you leaving their program and earning status on another program while flying their plane.