Pacer’s pedometer is an all-day, 24-hour activity tracker. The pedometer automatically resets to 0 at midnight each day, and it cannot be reset manually.
For iOS user, if you want to track your steps for a specific period of time, there is a secondary pedometer on the ‘Today's Activity’(Shoe icon) page precisely for this purpose. You can access the secondary pedometer by swiping to the rightmost tab of the ‘Today's Steps’.