How do I change from free activity to scheduled structured training, without having to save and start a new activity again?

On my garmin 965 watch, I start a running activity (or cycling activity), starting free activity, then I want to move on to a scheduled structured workout, and it won't let me or I can't find a way to do it, without save and start new activity. This is possible when I do cycling activities with my garmin edge 180 plus.