Hi and welcome to JustAnswer,Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, the only easy doable attempt would be to first gently apply pressure on the headrest and the legrest areas. While pressure is still applied, then try again returning the Panasonic to regular sitting position. This is to address the likelihood that the current full recline position is inadvertently causing a "lock" condition hence the motor could not initiate turning.
All others would be internal and would require referencing the repair/Service Manual.