Setting up an email trigger with certain conditions

Hello,

I have a reservation system as an App. It's for reserving facilities across our parks (Houston). Sometimes, constituents want to bring alcohol to their reservations. They select, from a multi-choice select field, yes or no (for alcohol). After they have submitted their reservation request, our reservationist goes into the system and changes an admin only field on their reservation from "new request" to "confirmed" (assuming everything else on their request checks out).

Houston Constables need to be notified of any alcohol reservation. 

I want an email to be sent to our constable correspondent's email address under these conditions: Our reservationist changes the constituent's reservation request from "new request" to "confirmed", and "yes" to alcohol must have been selected on their reservation request. 

Thank you.