Thank you for your question.
Kindly select a province of employment for box 10. You will then be able to click Continue. You will be directed to the T4 Summary page where you will be able to delete the unneeded T4 using the steps in this link: https://turbotax.community.intuit.ca/questions/1324151-how-do-i-delete-a-t-slip-in-the-online-edition-of-turbotax