Bare awareness while meditating in the Mahasi Sayadaw tradition

While practicing the Mahasi Sayadaw style of meditation, noting the rise and fall of the abdomen as the body breathes, and noting other intruding experiences or phenomena, and essentially labeling that which is noted, at what point does one dispense with the conscious labeling in favor of simple non-conceptual bare awareness? Is the transition made by conscious effort or is it a non-volitional event that one simply recognizes and sits with? I think I may have some fundamental misunderstanding in this matter.