Well, if you want to be snarky you could ask where the promoted agent now is so you can shop him/her as they are no longer at the scheduled site
Can you call tomorrow and see when the promoted agent is scheduled to be there because it was suggested you talk with him/her? Then get back with your scheduler, indicating the next date(s) that the target will be there and ask if she would like to extend the shop for you to visit then or how she would like to handle it. Since it looks like there was a miscommunication on your email, I would try to talk with your scheduler by phone. If you are still unable to get your scheduler to understand the situation and there is no "Plan B" available, I would just cancel the job because you aren't going to be able to shop someone who isn't there no matter how fast you spin your tires.