Carrier Services

[walkerx]

What is the app called on Samsung devices as need to reset it without factory resetting phone.

[SjorsK]

If I understand correctly you wish to reset the network operators.  Simply go to Settings -> Networks -> Mobile Networks -> Networks operators. 

Here you can turn "Select automatically off". This effectively resets the network operator settings. 

You might wish to check the Access Point Names as well to see if it matches with your provider (As stated in their documentation). 

[walkerx]

No it's the carrier services, most phones now use this. Not installed by default on Samsung phone so is there an equivalent

[Pugs1957]

If you are in the UK you don't need carrier services which can be found on Play Store

[walkerx]

Cheers