I copied this below from another thread I found. I will assume that you recognize this gets you into the Clinician's menu and you know to be careful with what you mess with in there. Were you wanting to erase data on the Smart card? This doesn't do that though I think there is some sort of little utility program that might reformat the card. This only changes the numbers you see on the LCD screen, the 7 day and 30 day average. Do you have the software? The software data remains unchanged and available for all days.
To reset LCD Therapy data (does NOT erase any data from SmartCard):
1. Hold down the (<-) (->) buttons while plugging in the power on the back,
wait for 2 beeps or 5 seconds, release buttons.
2. Press the (->) key and navigate to Therapy screen. (There is a minus sign in the lower right corner)
3. Press and HOLD down the (-) minus key for 5 seconds and/or until therapy data is reset to Zero.
4. Press the On/Off button to exit.