"Dear Ms. A___:
As one of Delta's most valued frequent travelers with 0 Delta SkyMiles, it gives me great pleasure to offer you the Platinum Delta SkyMiles Credit Card from American Express."
Thank you, SkyMiles Managing Director Jeffrey W. Robertson, for your kind offer, which I must decline. I am truly touched by your generosity. If you're still in operation next time I book a flight, I promise that I will consider your services. Along with every other airline that services my destination.
I've never been known for my brand loyalty.