How to auto update the SR status from "New" to "In Progress" after any updates made to the SR

Summary:

I would like to let SR be able to automatically update status from "New" to "In Progress" and I have set up a server script under Service Request object to trigger it Before Update,

The logic of the code is:

if the 'LastUpdateDate' attribute has been changed and the status is equal to 'New', set the status to 'In progress', I am pretty sure the 'LastUpdateDate' is changed after I made changes in the SR, but the script is still not been triggered.

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