How to implement Business rule for leave Withdrawal

Hi Experts,

We need to implement a business rule where withdraw for an existing absence is allowed only when the absence end date lies within 30 days from the date this withdrawal is applied. But we noticed that can cannot use a Global Absence entry validation fast formula for this specific scenario. Can anyone suggest how can we configure this in the system. Please not leave cannot be locked post approval since customer wants users to be able to submit changes on existing leave request wherein they will be resubmitted for approval. We can control editing existing leaves through the Global Absence