I've had a business MP visa for the past 3 years or so and am no longer getting that cards annual fee paid for, so I'm going to cancel and go with the one that gets me 3x on United purchases. I've read somewhere that they can deduct the signup miles if you cancel your card. Is that true? Also, I assume I still get the signup miles for the new card since it's past 6 months since I applied for one?