This can easily be accomplished by setting your phone to airplane mode or turning on Do Not Disturb. Additionally, you can reject any incoming calls, sending them straight to voicemail.
Apple Visual Voicemail is a quick & easy way to scan & manage voicemails on screen. Simply tap the voicemail icon on your iPhone to see all your voicemails as a list on your screen. No more calling up to listen to your messages. View and manage the list of voicemails from your handset screen. Pause, stop, replay, fast forward, call back, and delete messages on screen. Change your voicemail password and manage greetings

Open your phone’s voicemail app, then tap (or in some cases, tap and hold) the message you want to save. You should be presented with a list of options; the save option will usually be listed as “save”, “save to phone,” “archive,” or something similar.
I called customer support. They were not able to fix it and made it worse. Now it rings once instead of three times. They put in a service request and said it would be 1-3 days. Now they say 3 to 5 business days. I don't understand how something so simple could be such a major problem. I just wanted them to change the number of rings to at least 7. Disconnected the 1st of the junction boxes at top of door. Phone line rings after doing this so proves problem is in the home. I then ran a new wire pair to the NTE5, problem then came back, even with the pull out isolation port or whatever it’s called. Then wired direct to the back plate if that’s the correct term, phone starts ringing again.