Is there any way to send a follow-up/reminder for anyone who has a pending feedback email they have yet to complete?

We do not recommend sending email reminders to users who have not provided feedback. Why not? Here are two reasons:
1) Reminding your end-users to provide feedback might at first increase the response rates but our experience has shown that the ratings and feedback will most likely move towards a neutral score.
2) When feedback shifts towards a more neutral score, it can often be attributed to the passage of time since the service was experienced. Asking users to rate a service after a significant duration may lead to less accurate assessments, as memories of the experience tend to fade. For instance, rating an Uber ride weeks after the ride may not capture the nuances of the experience, resulting in a rating that does not fully reflect the user's true perception.

Instead, we have observed customers approaching this topic differently. While it may require additional effort, the potential benefits make it worthwhile. Within your ITSM tool, consider investigating the group of users who have not provided any feedback. Segment them into focus groups and engage in discussions to understand why they are not providing feedback. During these sessions, emphasize the importance of feedback and how it directly impacts the quality of service provided.