And if I leave in the middle of the process, can I redeem a partial reward?

No, if you decide to leave the audit process before its conclusion, you will not be eligible to receive a reward. In addition, a fee of 2 KNNs will be charged for the operation, and your responses sent up to that point will not be taken into account in the validation process. It is important to keep your tokens in the stake pool for the minimum period stipulated in order to be eligible to receive the reward.