The OPs last post explains that the customer screwed up. I would play & don't say a word just play, no excuses. If the customer mentions anything at all about your performance either the day of the gig or while trying to get a call back at a later time then you mention the fact that due to the date change one player had to drop out. Then say something like "we did everything we could so salvage the unexpected date change for you, I thought we did very well". The BL will have to get a feel for when to mention that, if at all. If all goes swimmingly well nothing needs to be said.