The phrase "having an effect on" can be replaced by a variety of synonyms, depending on the context in which it is used. Some examples include influencing, impacting, affecting, altering, modifying, transforming, changing, shaping and molding. Each of these words carries a slightly different connotation and can be used to describe specific types of effects. For example, influencing might refer to the way a person's behavior or words affect another person's thoughts or actions. Impacting might describe the way something physically affects or damages something else. By choosing the right synonym for "having an effect on," writers can convey their intended meaning more precisely and create a more nuanced and effective message.