Who Me Too'd this topic

Hello,

I have the following question for which I could not find a clear answer seaching the internet.

We use: Cisco Unified CM Administration

System version: 6.1.4.1000-10

We have a ISDN number block of a hundred numbers (488) 5000 - 5099, my number for instance is (020) 4885033

Now the way it works with external call id, is when you dial outside the main office number is displayed which is 5000. Now what I want is to change this for a single (or a couple of) user(s). I want his external caller id to be his actual extension number which is 4885001. I've tried from the Directory Number Configuration, External Phone Number Mask set the number but for some reason this is ignored or overulled by some overall setting. How can I get this to work?