The Purple Coat by Amy Hest, 1986.

Every year in the fall, Gabrielle and her mother travel to the city to visit her grandfather’s tailor shop. While her mother shops at other stores, Gabby and her grandfather have lunch together (Gabby always eats the same kind of sandwich), and her grandfather makes her a new coat. Gabby always gets the same kind of coat, and it’s always navy blue.

However, this year, Gabby wants something different. She wants a purple coat! She also wants it in a different style than her other coats, and she wants it to have a hood. At first, her mother and grandfather can’t believe that she really wants something so different from what she usually gets, and they point out that navy coats are classic, but Gabby is insistent.

Gabby worries that her mother won’t let her get the coat that she really wants, but her grandfather remembers that when her mother was little, she once wanted something really unusual herself: a tangerine-colored dress. Sometimes, people do want to do different things, just to have a change and try something new. He also thinks of a way to give Gabby what she wants while allowing her to go back to her classic navy when she feels like it. Gabby’s new coat is reversible!

This is a Reading Rainbow book.  It is currently available online through Internet Archive.