So I wouldn't recommend that route I think you have to go through the whole 'eligibility check' thing again via this page: https://www.amazon.com/gp/product/B07YVVX6LS?pf_rd_p=183f5289-9dc0-416f-942e-e8f213ef368b&pf_rd_r=32A6Q2M9RTSNGS66B8DM

and provided you're signed into your Amazon account it will detect you've already been approved by Citizens One (I'm assuming you were :D) and then you click checkout, then shipping, then payment options, and select the new mysterious Mastercard that's appeared in your payment methods and ta-dah!

Good luck, hope this helps!