You can reset the scale by removing and reinserting the batteries from the scale or replacing the scale batteries with new batteries. Make sure that you do not use rechargeable batteries, but alkaline batteries (not Duracell). Should you replace the batteries with new batteries make sure that you replace all batteries with the new batteries at the same time.

Resetting the scale does not affect the profiles created in the scale. They will not be deleted. Should you wish to change the profiles, you can do so by following the steps in the scale's manual. It is important that once you have changed a profile in your scale, you take a measurement of the person belonging to that profile, otherwise the changes will not be saved.

Read more here: How can I delete a user profile from my consumer scale?