There are several synonyms that can be used instead of the phrase "and so". These include "thus", "consequently", "therefore", "accordingly", "hence", and "as a result". These words are often used to connect two related thoughts or actions. They serve as a transition between them, indicating that one is a result of the other. The use of synonyms is not only helpful in avoiding repetition, it also adds variety and depth to writing. These words have a strong impact on the reader as they create a sense of closure and finality to the previous idea, paving the way for a new one.