You may need to prevent an automated review cycle from launching automatically if the rule is configured to auto-launch cycles. After canceling auto-launch, the review cycle will become a draft. You can verify, create, and launch the draft at a time you choose.
Navigate to Admin > Performance > Reviews > Automated Rules.
Select the Automated rule that contains the review cycle you want to prevent from launching.
Use the ellipsis ... button and then select Don't launch automatically.