"Tomorrow afternoon, perhaps? We could start with lunch and then a tour of the city. I'm sure that Wayne Enterprises could do without me for the day."
In fact, Wayne Enterprises did without him more often than some might expect. Lucius Fox certainly kept things running and did quite a lot to cover for the fact that Bruce often had other engagements. This would simply be a little bit less aggressive than some of the things he did in the name of the Bat. Even if he did have a secondary mission to learn more about the superheroine.