During combat: if a PC wants to gain a second maneuver (up to an absolute maximum of two - with very rare exceptions), the CRB states this is possible by:
1. Using an ability/talent that allows a free maneuver.
2. Spending two Advantage from a previous skillcheck.
3. Voluntarily suffering two strain.
4. Downgrading your action.
Without having the option to use 1 & 2, can I voluntarily suffer strain and still take an action? Or do I have to suffer strain AND forfeit my action to take a second maneuver?