Zeolitic materials with modified surface composition, crystal structure, crystal or particle size, and/or porosity, methods for making the same, and methods for converting oxygenates to olefins using the same are provided herein. In an exemplary embodiment, a method for reducing a surface silicon content of a silicon-containing zeolitic material is provided that includes providing a silicon-containing zeolitic material; and contacting the silicon-containing zeolitic material with a modifying solution comprising one or more of an amine, an alcoholamine, and an amino acid. In this embodiment, the contacting occurs under conditions suitable for the modifying solution to reduce a surface silicon content, increase the porosity, and/or decrease an average crystal or particle size of the silicon-containing zeolitic material.