source: How do i delete my voicemail greeting on the pantech burst at&t and set it to the standard greeting the phone brings? angietraviss said: but if there is no option to delete greeting, just to change/rerecord Was this comment helpful? Yes | No jai87 Level 10 (Genius)
Can’t record a custom voicemail greeting on iPhone? You need to try out a few troubleshooting workarounds to throw out the problem.

By using the reset network settings, an effectiveoption to solve network related issues, you can fix allthese problems by simply resetting the networksettings of your iPhone as it will clear all the networksettings, current cellular network settings, saved Wi-Finetwork settings, Wi-Fi passwords, and VPNsettings How do you reset your voicemail greeting? From the Home screen, tap the Phone icon . Tap Voicemail then tap Greeting (upper-left). Greeting islocated in the top-left corner of screen. Tap Custom to record a greeting. Enabled when a checkmark ispresent. Tap Record to begin recording the custom greeting message. Tap Stop to end recording then tap Save. How do you change voicemail settings on iPhone? Go to the Phone app, then tap the Voicemail tab. Tap Set Up Now. Create a voicemail password, then tap Done. Enter your password again to confirm it, then tap Done. Select Custom or Default. If you choose Custom, you can recorda new greeting. Tap Done to save your greeting.
This will initiate a call to your cell carrier’s automated voicemail setup, allowing you to configure your Galaxy S20 Ultra’s voicemail system.