How to change sample from poly to mono mode

Can anyone tell me how to change a sample from poly mode to mono mode in the 4000?

you can set the polyphony in the program menu / pitch (f3)..
default setting is 64... set it to 1..

I think ol boy was talking bout stereo to mono, not polyphony...
Go to sample > trim/lp > edit > and then scroll to the right, right after time stretch is stero to mono and mono to stereo. Did you steal your mpc from someone's studio? Because that should be covered in the manual. I wouldnt know though because I have never used the manual. Seems to be pretty self evident to me.