How to change your extension number in Outlook
Go to Microsoft Edge
Open this link https://isdselfservice.corp.mcb-group.bnk/
Once the portal logs you in, it will open on the Self-Update window (See Below)
On the right corner click edit
At telephone number fill in your extension number as follows (5999) 466-xxxx Office location (See below).
6. When finished, click update and the portal will synchronize these details with Outlook (See above). The synchronization will take a while before becoming effective.