Depositing to become an Ethereum validator sets two separate things: the key that signs on the network's behalf and the credentials naming where the stake can eventually return.
Two keys with different jobs
The validator key signs attestations and block proposals continuously, so it must be available to online software at all times.
The withdrawal credentials determine the destination for exited stake and accumulated rewards, and they are not needed for routine operation.
The separation means an operator can be given signing capability without ever being able to redirect the funds, which is what makes delegated staking arrangements workable.
Credentials are fixed in the deposit
Withdrawal credentials are committed at deposit time and become part of the validator's record on the consensus layer.
Once set to an execution layer address, they cannot be changed, so an error at deposit is not correctable afterward by any operator or service.
This is why deposit data is checked carefully before submission, and why staking services publish exactly which address will receive returned stake.
Withdrawals are automatic, not requested
Once credentials point to an execution address, the network sweeps validators on a rotating schedule and moves excess balance to that address without any transaction being sent.
Balance above the effective staking amount is treated as reward and swept periodically. A validator that has fully exited has its entire balance swept.
Because these are protocol-level operations rather than transactions, they consume no gas and cannot be initiated, accelerated or blocked by the recipient.
Exit is a queue, not an instruction
Leaving requires signing a voluntary exit message with the validator key, after which the validator enters a queue that limits how many can leave per period.
The limit protects the network from a sudden loss of validating capacity, and the wait extends when many validators exit at the same time.
An exiting validator must continue performing duties until it is processed, so operators cannot simply shut down without incurring penalties during the interval.
Why this matters when choosing a staking arrangement
In a delegated arrangement, the operator holds the validator key while the depositor should hold the withdrawal address. Confirming that split is the substance of the arrangement.
Where a service controls the withdrawal address, returned stake reaches the service first and the depositor's claim is contractual rather than enforced by the protocol.
Liquid staking tokens work this way by necessity, since the protocol must receive and redistribute the stake, which is why their contract permissions and redemption mechanics deserve the same scrutiny as the yield.