When it comes to writing, repeating the same phrases over and over again can be tedious for both the writer and the reader. Therefore, it is important to have a good understanding of synonyms to avoid this. For the phrase "working at", there are several synonyms that can be used to add variety to your writing. Some options include "employed by", "engaged in", "occupied with", "working for" and "tasked with". By using these different expressions, you can make your writing more interesting and engaging, while also avoiding repetition. So, start experimenting with these synonyms and take your writing to the next level.