Users cannot withdraw funds once deposited into a Perpetual Vault, however they will receive the returns generated by the vault in perpetuity. (Perpetual Vaults put a user's capital to work perpetually).
If a user did want to liquidate their original deposit they cannot withdraw it, however they can sell or transfer their Perpetual Vault Token (PVT) that was minted and sent to their wallet at the time of their initial deposit.