The phrase "stood in" can be used in a variety of contexts, including as a substitute for another person, taking someone's place temporarily, or being in a particular position. There are several synonyms for "stood in," such as "substituted," "filled in," "stood for," "replaced," and "covered." Each of these words carries a slightly different connotation and may be used in different situations. For example, "substituted" may be used in the context of sports, while "replaced" may be more appropriate in the workplace. By using synonyms, you can vary your language and express yourself more clearly and effectively.