Answer:
A way to distance herself from her past.
Step-by-step explanation:
In "Everyday Use," Dee is one of the two daughters of Mama, the other one being Maggie. Dee is very much defined in contrast with Mama and Maggie. While Mama and Maggie are very traditional, generally content with their lives, and not very curious about the world, Dee wants to receive an education, travel and understand social and political matters. As Dee realizes how different she is from the rest of her family, she changes her name. This is her way of embracing a new identity and distance herself from her past.