You can make changes to an ongoing ride without starting a new Activity.
Changing Profile mid-ride
You can change the selected profile from the Control Center.
The ride does not need to be paused to do this.
Just scroll down from the top of the screen to access the Control Center.
Add/remove/change Route mid-ride
You can add, remove, or change the route during a ride.
You can also do this from the Control Center without pausing the ride.
Add/remove/change Workout mid-ride:
You can add, remove, or change a workout after pausing a ride.
You will see the option on the Workout Screen.
To add a workout mid-ride you must have a workout page in your selected profile.