Did you forget to change your driving status, or do you suspect there's a mistake?
You can change the Hours of Service Log in the Samsara Driver App.
To do this, tap the "Log" button, then the day of interest, and tap on the log chart.
Edit the start and end times, and the status that you wish to apply. Enter a remark for the edit. Whatever you add will overwrite the existing duty status for that the times selected. Note that you are unable to edit automatically created driving segments, as per FMCSA regulations.
Tap 'Save log update' at the bottom right of the screen to save your corrected logs.