Most fare rules which allow standby will also allow a routing change. The problem is that when the routing changes, the agent entry to place a passenger on standby becomes challenging.

When the routing does not change it is a few simple keystrokes (alternate flight entry) and the original e-ticket remains "attached" as well.

When the routing changes, in many cases the alternate flight entry cannot be used as an error (does not match etkt) appears. Trouble begins to brew. There are ways around this; but, very few are in the know.

The problems begin at this point. Most agents convert your e-ticket to "paper" and build a standby segment which will be seperated from your original PNR aka without your WP#.

It takes some dillengence on both parts to make this work; but, it is permitted. The key is to be sure that the agent has also "listed" you on a flight from DTW to your final destination and has given you that coupon as well. Be sure to check the PNR (confirmation number) and if it appears different, be sure that you ask to have your FF# entered into the standby listing as well.

The good thing is that most agents will just rebook you if your fare bucket is available i.e. V T K etc in your original reservation and drive your boarding passes. Things only get tricky when you need to "StandBy" for the flight.