the bottom 3/4 of my plant is ready to harvest, but the cola is not ready and still needs a week or two to finnish. Can i take that much off the plant and leave the cola on to ripen? or will i kill the plant?
Sure.
If your sure those buds are done.
after you cut those the plant might go into shock for a couple 3 days.
but afer that it should have more energy to flower your colas.