I'm not really familiar with fl studio, but I doubt that can be done as it would require real time warping.
You could bounce it and transpose it, but that would change the tempo too, which could be fixed by warping, but that could hurt the quality and feel of it.
Unless it's all audio I think I would try to bounce the audio channels and transpose/warp just them, change the pitch of the midi channels manually, and then listen through it to see if the audio quality is good enough.
Dunno about fl studio, but ableton live has a plugin that can transpose midi clips for you, might be something like that in fl studio too.