Changing from 4/4 to 2/2

Perhaps I am being ignorant, but when I insert a cut-time signature in the middle of the piece and then change the types of notes to compensate (e.g. 1 quarter note=1 half note), it is played back as if the section in cut-time is in 4/4. Is there a way to fix this, or will I have to change the half notes back into quarter notes, etc.?