We study theoretically the reflection of the transverse-electric and transverse-magnetic waves from the surface of semi-infinite layered superconductors in the presence of external dc magnetic field. The superconducting layers are supposed to be perpendicular to the boundary of the sample. Due to the strong anisotropy of the irradiated sample boundary, the transformation of the wave polarization occurs after its reflection. We show that, despite the relatively small penetration depth of the dc magnetic field, it affects qualitatively the field distribution of the electromagnetic wave and, therefore, the reflection and transmission coefficients. Thus, the external dc magnetic field can serve as an effective tool to control the transformation of the wave polarization. We obtain analytical expressions for the reflection and transmission coefficients and define also the values of parameters, when the most effective transformation of transverse-electric waves to transverse-magnetic, and vice versa, takes place.