This question is similar to the most challenging project question. You should pick up a challenging project, define the success criteria and tell it in a story form.
Sample answer is:
In our company, we sent emails to customers for information about their accounts. These emails are sent by different departments and on different occasions. Due to which a customer may get two emails on same day. The system to sent emails was not centralized. Business came up with the requirement to send SMS/Text notification also in certain cases. I decided to refactor the code and make it generic to handle email as well as SMS notifications.
I presented my idea to the team and created a design for centralized system that can send different kinds of notifications as well as maintain customer preferences for notifications. We formed a team and implemented this project in 4 months. We provided API to different applications to use our system. With this approach we provided a generic solution that overcame existing issues.
Business partners were very happy with the new system. Their manual work was reduced drastically after this project. It was a great success and mentioned in our company’s top 5 projects in all employees’ meeting.