During periods of rental the car is covered under the YourDrive commercial insurance. At all other times, when they car is being used for personal use, it remains covered under your existing personal insurance plan. The two insurance policies work in parallel with each other and should not impact each other. There should be no need to contact your insurer, nor should you upgrade your personal car insurance to commercial car insurance.
All the details of how our insurance works can be found in our Terms and Conditions.