You cannot do that with sim cards on the Sprint network.
Try the following:
Turn off the Boost Mobile phone and remove the sim. Turn the phone on again without the sim and you will get an error message. Turn phone off and replace the sim and turn the phone on again.
If it does not work, then follow the steps for carrier reset and service update indicated below. You may need to do the carrier reset several times.
https://help.ting.com/hc/en-us/articles/205428688-Completing-Activation-for-an-i OS-10-and-up-device
If that does not work, you can try two other things:
1) If you see No Service or Searching on your iPhone or iPad - Apple Support
You may need to do a reset to factory settings and restore the operating system.
2) contact Boost Mobile, explain the situation and request assistance if you cannot resolve the matter.