No matter how good your management training is, it’s useless if you don’t have knowledge and experience of the tasks involved in serving in an à la carte restaurant.
Such training is merely an addition to your existing position. There are several reputable restaurants that have supervisors who have had no previous experience working as a waiter.
The consequence of this is that it leads to high staff turnover and a poor working environment. If you have previously worked as a supervisor in another type of restaurant and service, you should not start as a supervisor in a new restaurant where you have no knowledge of the business. This will only irritate the staff.