When a Pilot determines that he/she will not be able to have 8 hours uninterrupted sleep opportunity and contacts the Airline, the clock is reset to just permit the 8 hours of sleep opportunity. It does not start a new rest period.

This differs from when the Airline contacts the crew member during the rest period, where the clock will need to be reset to permit the 10 hour rest period with the 8 hour sleep opportunity.

McEldowney – (2014) Legal Interpretation