Just wanted to give my experience of downgrading my BA Amex Premium Card (Black one) to a free card (Blue one).
Decided that the annual fee and the spend was not worth it anymore currently due to no corporate travel, no expenses I have to make on that card currently or for the foreseeable future.
And in regards to any insurance, I was already paying for Revolut Metal due to the 1% cashback abroad and no FX fees so already have this travel insurance + another personal travel insurance.

So my main reasons to downgrade:
- Currently pointless to have a travel and expense based travel card with annual fee due to no travel for work or private
- No upcoming large purchases to be made before card membership ends / is renewed
- No need for the extended coverage
- Using paid Revolut Metal card (= actually MasterCard Premium Travel card) abroad for no 2.99% FX charges like Amex + instant 1% cashback on non GBP spent.

Process:
- Was connected to the "card downgrade team" in less than 1 minute (0800 UK number).
- Agent confirmed that any issued BA Amex vouchers would remain valid, card downgrade does not involve any credit checks, just a soft eligibility check (asked the usual questions about job description, time at current address, annual salary)
- Membership fee is prorata refunded as statement credit
- Card number doesn't change for convenience of linked services and existing card remains usable until new card is activated
- New card is sent within 10 working days, any linked partner cards will stay the same
- All other contractual items (AER, Credit limit etc..) remain the same
- The alternative amex insurance policy from the blue card is activated immediately and policy will be sent via email

In total, process took less than 10 minutes and also received a 5 GBP additional statement credit for not cancelling the card completely.

Hope this helps is someone else has questions about downgrading the BA Amex card to the one without the annual fee.