If you want to limit the list of users that receive NikaTime's messages and can interact with her, go to the Team Members page, select the users using the checkboxes on the left column, click the Edit button, and toggle Time Tracking On for those you wish to track, and Off for those you don't.

You can also use the toggle button on the Tracking column.

Note: When you deactivate tracking for a certain user, they won't be able to interact with NikaTime anymore (on Slack or MS Teams), nor add records through the Report Center.

If your teammate doesn't want to receive NikaTime's reminders but still wants to track their time, it's possible to mute their conversation with NikaTime.