The phrase "one at the controls" refers to the individual who is in charge or responsible for operating a system, machine or vehicle. Various synonyms can be used to replace this phrase, such as "in command," "in charge," "piloting," "managing," "directing," "steering" or "guiding." Each of these alternatives suggests a skilled and knowledgeable person who is in control of a given situation. It is important to use precise language in communication to ensure that the intended meaning is conveyed effectively. Synonyms provide great alternatives to add variety to language and avoid repetition.