Setting SMS sending number

[kaldewei]

How can I set SMS sending operator's central number?

[_alexdon_]

Messages-settings-message centre.

[kaldewei]

Thanks for your quick help.

I tried it but in that field value is not changeable. Adjusted value is "unknown"

Is there any other chance for this modification?

[_alexdon_]

Contact your network operator and see what they suggest.