A PCI adapter card hosting non-vital system resources can be removed if the device driver supports hot-plugging.
A PCI adapter card is not detachable if it is a vital system resource. For a PCI adapter card to be detachable:
The device driver must support hot-plugging.
Critical resources must be accessible through an alternate pathway.
For example, if a system has only one ethernet card installed in it, the ethernet card cannot be detached without losing network connection. This replacement requires additional layered software support to keep the network connection active.
See "x86: How to Remove a PCI Adapter Card" for step-by-step instructions on removing a PCI adapter card.