Is it possible to/how do I change the CSC of an android phone

I apologize if I did not formulate the question correctly however I'm a 'noob' regarding Android versioning and Android ROM software etc. Here is some background regarding my question. I bought a 'not simlocked' phone from a retailer here in the Netherlands. With the intention to buy a sim only subscription from a network carrier as this was 50 euro's cheaper. Note that the network operator is also Dutch. On the website of the network operator it shows that the Samsung Galaxy A5 2017 supports Wifi calling at that provider. However I do not see WiFi calling in the options. I suspect this is because the CSC on my retail Samsung Galaxy A5 2017 is not the same as a Samsung Galaxy A5 2017 bought at Tele2. The Samsung helpdesk of my country says it should be possible if you insert a Tele2 simcard. My question is, is it possible for me to change the CSC of my android phone to that of the CSC of Tele2/My network carrier as I would like to use WiFi calling. Inserting the Tele2 simcard does not change anything with the software.