You can choose another book from your partner's catalog instead of the suggested one, as long as you do it before the delivery date.
- Go to the Benefit tab in the app.
- Tap your partner's logo.
- Choose a new book.
- Tap Choose this book.
That's it! Now just wait for the delivery date, which appears on the partner card. Until then, you can switch books as many times as you like, and you'll receive the last one you selected.