What if I can’t get the SIM card drawer open to return the phone?

Press in more firmly. If its never been opened, it may require more pressure than you think.

But as I said, if your service has been transferred to the new device and all is working correctly, then it does not matter. You can leave it in.

If you are expecting some other way to do it then that’s not going to happen. You’ll to take it in to an Apple Store or authorized Apple service center if the SIM is jammed or won’t spring out.

Why can't you?

Unless you had your carrier transfer your service to your new device, you may want to take out the sim card as it holds your phone number and service plan settings.

If you have had the service transferred to the new device, then it doesn't matter.