You can reattach a PDL LUN after it has been removed.

1

Return the LUN to working order.

2

Remove any users of the device.

You cannot bring a device back without removing active users. The ESXi host cannot know whether the device that was added back has changed. ESXi must be able to treat the device similarly to a new device being discovered.

3

Perform a rescan to get the device back in working order.