Why does Cameron have to break his date with Avery in "A Big, Bold Lie"?

Cameron gets a call from Simon Brinks' assistant telling him that Brinks has been out of town, and she apologizes that it has taken so long to get him an appointment. She arranges for Cameron to meet with Brinks in Seattle at 6 p.m. Cameron is scheduled to see Avery that afternoon, so he stops by the store and asks Marco to tell her that he has a meeting he has to attend and has to break their date.