The phrase "is in to for" can be broken down into three separate words, each with its own set of synonyms. "Is" can be replaced by words like exists, occurs, or happens. "In to" can be substituted with phrases like interested in, engaged in, or involved in. And "for" can be interchanged with terms such as for the sake of, with regards to, or pertaining to. Having a range of synonyms at your disposal can help to vary your language and make your writing more interesting and engaging. However, it's important to choose the right synonym to ensure your meaning remains clear.