If you have questions about the conjugation of возница or Russian nouns in general, you can practice and get feedback from a professional tutor.
Две мыши обернулись возницами, а два голубя стали рысаками
The two mice were the coachmen and the two pigeons were the horses.
Побудь один день не конём, а возницей.
For instead of a horse, why the coachman, of course.
Get a Russian Tutor