You can not change it, it is the original phone number that is stored on the SIM CARD most people will have a different number as they have ported or transferred a number to that sim.
Yes you can change it, reset your phone.
This happened with me while setting it up, I put in the new sim number, turned it on then realised I wanted to keep my old number :).
Use Samsung switch then reset it, not a problem at all, always fun to start over again
Samsung S8 Plus: I bought a new SIM and requested to keep my old phone number. When I look in Settings > About Phone it still showed the SIM's original number and not my actual phone number.
To change it I did this:
1. Tap on 'Contacts' You should see an icon or picture at the very top of the screen, possibly your name and the words 'Share Profile'.
2. Tap the picture/name to edit your profile.
3. At the top of the 'Edit Profile' screen tap on 'EDIT'
4. Now you can enter the correct phone number along with additional profile information.
5. Tap 'SAVE' when done.
Go back into Settings > About Phone and you will see the number you enterd into your profile info.
Went into contacts.
My details at the very top with the wrong number.
Tap on the circle and it opens just the my contact page.
Right at the top it says edit, tap.
It then opens up but in edit mode.
It wouldnt let me edit the old number that is there....it just stays greyed out.
But...... If you press the minus button next to it, it will delete it. You can then tap the plus and type a new number in.
Change anything else you want to put on your contact card and save it.
Hey presto problem solved.
Thanks for your input, but it does not change the phone number in the SETTINGS>ABOUT DEVICE>My phone number. That number still remains the same as the original phone SIM number when the phone was purchased. At least in my or my wifes' Samsung S7 it does not. Also it does not in a Samsung S8 as advised by the staff in the EE office in the town of Reading in the UK.
OK. To clarify this for future questions on this subject, here is the official Samsung answer from Chat.....
Your Samsung phone reads the phone number originally assigned to the SIM card and if you are no longer using that number (such as when you've ported over your old number to use with the new SIM card) your phone will no longer know what number your are using. Your phone in this case will list your current number as 'unknown' or present the number originally assigned to the SIM card.
This information cannot currently be amended due to how the Android operating system registers a number to the handset upon first use. The issue may be resolved in a future Android software update, but until then rest assured that it has no effect on your device's functionality.
Yes, this is correct in my case, too. I had to have my phone carrier issue a new SIM card and the problem went away. The old number is "hardcoded" in the SIM card, as will be the new phone number with a new SIM card.