Losing a Promotion Code

Hello there. I'm a new subscriber to the Ultimate Game Pass, and after I bought it, I found out that there are promotion codes that you can get from the perks section on your computer desktop Xbox app, I clicked on one of them by mistake, "Sea of Thieves", without being ready to redeem it, and I completely lost it due to not knowing that once I open it I can't open it or find it again anywhere else. My question is, how can I retrieve the promotion code that I lost, or get a new one? If I am unable to receive it or receive a new one at least, it is definitely a huge disappointment as to the fact that it was the most important perk on the "perks" page to me.

Regards,

16

:)