You have two choices :

1. Have as destination of this leg n°28 an intermediate airport of your choice, and continue the tour with leg n°29 by making a departure from the same airport of your choice to LFSYT - Strasbourg Entzheim for the event.
2. To not do this leg n°28, and directly go to the leg n°29 to LFST - Strasbourg Entzheim from LFRB - Brest.