This isn't going to work for all carriers. On mine (AT&T), calling my own number dumped me into the audio voice mail menu and didn't record. You could always try calling the person on the other line again—you'll go directly to their voice mail, certainly. They could send you the recorded "voice mail" conversation after. However, that's not something most interview subjects want to get involved in.
My iPhone rings for 15 seconds – which is actually eight rings – before it goes to voicemail, but even that’s not long enough if I’ve put the phone down in another room or it’s zipped into a pocket in my jacket.

2. Hi, you’ve reached [your name]’s voicemail box. I can’t come to the phone right now, but if you leave your contact information I’ll get back to you within 24 hours.
After creating, the Voicemail Greeting, you can test it by calling to your number from another phone, and see if it is playing correctly or not. Open the Phone App. On the lower screen, tap on the Voicemail option. Select Custom, with this option, you can record the personal voicemail greeting on the iPhone. Tap Record, to start recording the voicemail greeting message on the iPhone. Greeting samples are given in this article below, Once you are done with recording, tap Play to listen. Lastly, if everything is alright, and custom voicemail recording is perfect, then tap Save.