There are several synonyms for the phrase "errand girl," all of which depict someone who is responsible for running various errands or tasks for someone else. Some possible alternatives include "gofer," "personal assistant," "runner," "fetcher," "courier," and "messenger." Each of these terms highlights the idea of a person who is tasked with completing various tasks on behalf of someone else, such as picking up packages or delivering messages. While many of these terms have a gender-neutral connotation, some like "errand boy" and "errand girl" may connote gender roles, and it's important to choose language that is inclusive and respectful of all people.