CANTalon Speed vs Position PID

When controlling a CAN TalonSRX with closed-loop PID, how do you change between Speed and Position PID? Set appears to take either a voltage or position, depending on the mode, but I’ve been unable to locate a way to change the mode itself, if one exists.

If it’s important, my team uses C++.

Checkout out section 3.6 in talon srx software reference manual.
http://www.crosstheroadelectronics.com/control_system.html