Originally Posted by
websteth
I don't think I have ever seen a product change to offered a signup bonus. I've done a couple PC just to avoid another pull and I've never been offered a bonus. The only exception I will say is AMEX will sometimes target a change from a lower card to a higher version (Delta Gold to Delta Platinum) but you then will not get the larger signup bonus that is offered to new card holders.
At this risk of going off topic, because I agree with your general premise that Chase will not offer points for an upgrade, it is worth noting that you can get the Amex upgrade offers IN ADDITION TO the initial signup bonus for a higher end card. This is one of the best work-arounds to Amex's once per lifetime policy. To extend your example: open Delta Plat, get reward and cancel after a year. Open Delta Gold, get reward, and hold onto hoping for upgrade offer back to Delta Plat. I assume you already know this, but for anyone else looking in hopefully this opens a new points-earning avenue to you!