Upgrading and Downgrading a BA Amex

[Ant_]

How feasible is it to upgrade to the premium BA Amex just before hitting the £10K spend, then once the voucher is issued downgrade?

[Guernsey Globetrotter]

Well the upgrade can be done automatically via this link so no problem with step one as Amex actively encourage it:
https://www.americanexpress.com/uk/benefits/upgrade/ba-premium-plus-credit-card/

Step two is a bit more tricky as repeatedly doing this may be something that Amex frown upon. Nevertheless, I’d have no qualms trying it (or indeed cancelling the card altogether) if this is your first time round.

Personally, I prefer the cancellation route as you can then have P2 get a referral bonus when you reapply for the card when you want to do next year’s companion voucher cycle. Just be aware that rinsing and repeating this may not be great for your credit rating or your long-term relationship with Amex!