Move back to India

Hi All

I have already submitted my documents with AOR date of 11th September 2018. My profile says “Medical Passed” so far and my application still seems to be in IP1 stage. With current trends and processing times I will have to probably wait a while for the PR.
My H1B visa period is ending this month and I am planning to go back to India by the end of this month.
Does anyone know how to inform CIC about this? Will I have to submit any additional documents for this scenario?