how to design the power amplifeir with two o/p power level

i have to design the power amplifer which will give two set of powers one is 6dBm and other one 3dBm which depends upon the which modulation tech is being used ..
when it uses GFSK then the o/p power is 6dBm
and when its uses QPSK then o/p power is 3dBm.
can u suggest some circuit which can be helpful ..

I assume you want the same efficiency and distortion performance, otherwise just reduce the bias. You could have a balanced or quadrature pair and switch one arm out of circuit to run single ended. It may be possible to just turn off one arm and use pin diodes to provide a good short, given your reflections in the couplers add in phase.

You may also want to look into a Doherty amplifier as it has an extra amp for peak power.