I've had reps make up reasons before, but it's always been possible to convert after a number of calls. However, you will likely forfeit any unredeemed points.
Regarding bonus, you don't get one for switching. But the Travel Rewards signup bonus isn't worth a hard pull.
This card doesn't get used much, there's a minimal amount of points. And I agree on the bonus not being worth the hard pull, that's another reason I had to try to avoid it.
The reason for switching is the zero FTF with the Travel Rewards card, my other cards all have FTFs.
I got it done last night, over an online chat session, after the agent confirmed (again) it would be only a soft pull. Looking at my credit file this morning, I don't see any hard pulls.