  We propose and analyze a scheme for realizing tunable coherent perfect
absorption (CPA) and reflection (CPR) in a three-level $\Lambda$-type
atom-cavity system. With EIT-type interference induced by a coherent coupling
laser, the scheme provides a new method of attaining tunable near CPR at
two-photon resonance. By different coupling strength, the system can be excited
from linear CPA regime into nonlinear even bistable CPA regime without changing
the frequency of the probe field, where the hysteresis cycle of the bistability
is controllable. In addition, the CPA regime can be transferred into the near
CPR regime with controllable atomic coherence and linear absorption induced by
an incoherent pump field. Our work suggests a mechanism for manipulation on
extreme absorption (0% and 100%), which can potentially be applied in logical
gates and optical switches for coherent optical computing and communication.
