Originally Posted by pokee

I have never had a credit pull on an upgrade, and I suspect this is because you already hold the account. BUT I often wonder if the criteria for the card is different (minimum household income, for example) if they'd deny you or make you reapply over the phone and do the pull?

Originally Posted by JJonahJ

As pokee mentioned, when you do a product change (upgrade or downgrade) the account remains the same within your credit file, even if the card account changes to a new number.

I up-converted from a no-fee Airmiles card to a World Elite MC, which requires $60-$70K income. But, if the FI doesn't ask you to prove your income, you'll get the new card.
i.e., your credit file does not store your income info.