If I replace the ignition switch does it need to be Flashed?

Do you mean the ignition LOCK CYLINDER instead of the ignition SWITCH? .. Lock cylinder = the part the keys go into - - ignition switch is the electrical part behind the lock cylinder.. Furthermore - ‘IF’ the security light is blinking or will not turn off and engine will not crank / start then yes the vehicle is equipped with the Pass Lock anti theft system which does indeed require a “chipped key” The chip (resistor) is contained within the black plastic part of the key and is not visible. Best option is enlisting *hands-on* assistance from qualifying personnel for proper diagnosis before attempting speculative repair. Good luck!