New SIM activation: Do I need to reboot?
Usually a new sim card, before activation, will not be recognized by the phone at all (it will either say 'no service', or 'no Sim')

So, being that your phone recognized the carrier, it must be that the Sim is fully functional, and the reason that it says emergency calls only, is because the number wasn't fully ported, as you have stated.

Your phone should be able to detect automatically, the ability to make calls.
If it doesn't, then going into airplane mode for a moment should do the trick.

You can also keep trying to start a call, this will make the phone look for connection