Promised Delivery Date based on an event

Summary:

There is a way that the promised delivery date on the purchase order isn't filled with a specific date, but rather can be calculated based on an event?

Content (please ensure you mask any confidential information):

There are many cases where the supplier's promised delivery date is calculated based on 'days from receipt of the PO' (Purchase Order). For example, the delivery is 15 days after the PO is received.

In many companies, the approval process can take several days, and at the time of creating the PO, the buyer sets a promised delivery date within 15 days. However, if the PO approval is concluded 4 days later, the promised delivery date should also be delayed by 4 days.