HP EliteDesk 705 G4 MT Hardware Reference Manual page 25

c. If you are removing a PCI Express x16 card, pull the retention arm (1) on the back of the expansion
socket away from the card and carefully rock the card back and forth until the connectors pull free
from the socket. Lift the card straight up (2) then away from the inside of the chassis (3) to remove
it. Be sure not to scrape the card against other components.
9. Store the removed card in anti-static packaging.
10. If you are not installing a new expansion card, install an expansion slot cover to close the open slot.
IMPORTANT: After removing an expansion card, you must replace it with a new card or expansion slot
cover for proper cooling of internal components during operation.
Removing or installing an expansion card 19