Recently, the development of a versatile thermochemical nanolithography (TCNL) technique has been reported. It allows simultaneous control of the local chemistry and topography of thin polymer films. This technique can pattern sub 15 nm chemical and topographical features at the rate of 1.4 mm per second by inducing thermally-activated chemical reactions by means of a heated atomic force microscope (AFM) tip. TCNL is achievable in different environments and can easily be adapted to a variety of substrates and chemical functionalities. Here, we demonstrate that a thin polymer film can be chemically modified twice using TCNL to tune its wettability. We are able to write hydrophilic nanopatterns over a hydrophobic polymer surface upon a first step heating and then revert back to hydrophobic surface by a second step heating. This write-read-overwrite capability is particularly useful in data storage application and complex nanofluidic device design.