Recently, I was given a particle photon to play with by my manager at the end of my internship. However, this device has already been claimed and I could not get access to the owner of the device to get it release.
Is there a way to factory reset the device so it becomes unclaimed?
In general terms, it's not possible to do that. The actual owner must release the device before claiming it again, this is to prevent people from stealing them. Can you ask your manager to release the device?