Subaru 2015 BRZ Owner's Manual page 141

Navigation
5
When the destination menu is displayed, select the
route's start point by using the same method as
selecting the destination.
6
Set the new start point, and then touch
140 Navigation
7
The vehicle marker goes clear on the map, indicating
that there is no GPS reception. If a route is already being
navigated, it is recalculated using the position selected
at that time.
(Go!).
Go!
8
To return to standard navigation, touch
(Turn on GPS), and if a warning message is displayed,
select which operation to perform.
Turn on GPS