When it comes to finding synonyms for the phrase "allows in," there are several options to choose from. Some possible alternatives might include "grants access," "permits entry," "authorizes admission," or "enables passage." Other options might include phrases such as "lets in," "facilitates entry," or "welcomes inside." Depending on the context in which the phrase is being used, there may be additional options as well. Ultimately, the choice of synonym will depend on the writer's particular style, as well as the nuances of the meaning that they are trying to convey.