shipping calendar to have some days marked as blocked.

Hello Experts,

One of our mills is to going to be closed for maintenance for a few days. So, I have been asked to modify the shipping calendar for the same.

In SAP table TVST, I found that all the shipping points of this plant have the same shipping calendar Z4 assigned to it.

On checking Z4, in transaction code SCAL, I found that the holiday calendar assigned to it is ZW.

I have tried adding special rule to both the factory calendar Z4 and the holiday calendar ZW (assigned to it), for the required dates and saved.

I have then tried to create a delivery on those dates but system did not stop me or anything.I could complete upto goods issue.

I am not very clear as how this thing works. Can someone please explain the concept of blocking certain days in shipping calendar?

Regards

P.R