I just transferred to a new iPhone from an old one and it’s SOS mode

It could be that the OP does not want to turn off the Emergency SOS feature – but that he simply lacks cell phone service. You'll see SOS come up when the phone can't place regular cell phone calls, but can place 911 (or try to place) 911 ones.

This might be

• Because you haven't taken out a cell plan for the new phone with a carrier
• Because you haven't installed or activated the corresponding SIM card or eSIM
• Because you are in a cellular "dead zone" where there is no coverage

If you don't have a valid cell plan, then the carriers have no obligation to you – except, perhaps, to let you dial emergency 911 calls. I can see how the law, or the regulatory agencies, might make a exception, and say that you've got to let anyone (even a non-subscriber) dial THAT number.

If you see No Service, Searching, or SOS on your iPhone or iPad - Apple Support

Servant of Cats wrote:

If you don't have a valid cell plan, then the carriers have no obligation to you – except, perhaps, to let you dial emergency 911 calls. I can see how the law, or the regulatory agencies, might make a exception, and say that you've got to let anyone (even a non-subscriber) dial THAT number.

That is certainly the case in the U.S. As long as the phone will turn on and connect to the network, carriers need to put a 911 call through, even if the phone otherwise has not active service plan.