To change the destination target which is used for all your navigation and final glide calculations, simply tap on Target navbox or select Menu > Target panel from the main menu.
You are presented with choices of:
. List of nearest landable points (sorted by distance from your current position)
. List of your waypoints that are currently in use
. Recently used targets (last 3 targets that you have used for navigation)
. A quick list of interesting targets such as nearest landing option, last thermal, soaring begin & takeoff. Only items with sensible data are displayed
… and just in case you don’t want to navigate to a target at all, you can choose to clear the target