Ayon Das Mahapatra As far as the metal-semiconductor junction is concerned, I don't think that different biasing conditions can change the metal work-function in particular. Now under the biasing condition, the band bending at the interface may be tuned due to the migration of the defect. More specifically under different biasing conditions, the defects (especially vacancies) can migrate that may change the doping level of the semiconductor (also called poling effect) and Schottky barrier height of the metal-semiconductor junction too.

Thanks Mr. Paramanik & Mr. Saba for your valuable comments. As prescribed you that the band bending will only occur at the semiconductor side of the junction only. But I am just observing the scenario from a different angle. Electrons are more prone to go towards forward biased direction and repelled from reverse-biased direction. So, is it possible to find a change in the energy levels of metals biased in forward and reverse directions. ALike, work function energy of forward-biased metal side may be downgraded a bit and countered by uplifting of work function energy of reverse-biased metal side.