How to Chill
Stakers can assume any one of the three states: validating, nominating, or chilling. When a staker does not want to actively engage in staking - but does not want to unbond their funds either - they can choose to temporarily become inactive while keeping their funds staked. The act of stopping either nominating or validating is known as chilling.
An account can step back from participating in active staking by calling the chill extrinsic in
the staking pallet. When an account chooses to chill, they will become inactive
in the next era. The call must be signed by the controller account, not the stash.
Note: If you need a refresher on the different responsibilities of the stash and controller account when staking, take a look at the accounts section in the general staking guide.
Chilling as a Nominator
When you chill after being a nominator, your nominations will be reset. This means that when you decide to start nominating again you will need to select validators to nominate once again. These can be the same validators if you prefer, or a completely new set. Just be aware - your nominations will not persist across chills.
Your nominator will remain bonded when it is chilled. When you are ready to nominate again, you will not need to go through the whole process of bonding again, rather you will issue a new nominate call that specifies the new targets to nominate.
Chilling as a Validator
When you voluntarily chill after being a validator, your nominators will not automatically go away. As long as your nominators make no action, you will still have the nominations when you choose to become an active validator once again. However, if your nominators decide to nominate other validators then these nominations will take priority when the validator comes back. It may also be the case that your nominators change their entire nomination targets (all 16 of the allowed nominations). In this case your nominators would need to explicitly specify your validator as a target when your validator comes back.
When you become an active validator you will also need to reset your validator preferences (commission, etc.). These can be configured as the same values that were set previously or something totally different.
Involuntary Chills
If a validator was unresponsive or found to have committed a slashable offense within two Eras, the validator will be removed from the active set in a process known as involuntary chilling. When a validator has been involuntarily chilled, it is necessary for the nominators that were previously nominating that validator to re-issue the nominate call.
Nominators who have the option to renominate an involuntarily chilled validator will have a display row to do so using Polkadot-JS Apps. This row is displayed in the "Account Actions" tab for the nominator under a heading that says "Redenomination required". If your validator has been involuntarily chilled, you will need to request your nominators to re-issue the nominate call in order to start nominating you again.