HURRICANE TIP: If you lose electricity, phone service, & wifi, just update your voicemail message greeting to notify family and friends of how you are and keep them updated. You can change your voicemail greeting as many times as you want and can do it without data!
If you had a generic voicemail greeting and recorded a personalized voicemail greeting you can change to the custom voicemail greeting by saving your custom voicemail recording. You should first listen to your recording by playing it from the menu and can then choose to keep the custom greeting or revert to the default one. Don’t forget to confirm your changes by tapping “Save” when done. How do I change my voicemail message on Samsung?How do I delete my voicemail greeting on Android?How do I change the default voicemail on my Android?How do I manage my voicemail on Android?How do I change my voicemail greeting?How do you use voicemail on Samsung?How do I remove a name from my voicemail greeting?How do I turn off my voicemail message?How do I turn off voicemail on Samsung?How does voicemail work on Android?What is my voicemail PIN?What is the best voicemail app for Android?How do you unlock voicemail on Android?Is there a voicemail app for Android?Does Samsung have a voicemail app? On Android devices above Android 5 (Lollipop), open the Phone app. Then, press and hold “1” to call your voicemail. Now, enter your PIN and press “#”. Press “*” for the menu. Press “4” to change settings. Press “1” to change your greeting. Tap the three dots (upper right corner of screen) Tap “settings” Tap “voicemail” Tap “advanced settings” Tap “setup. Tap “voicemail number. Enter your 10-digit phone number and Tap “OK. Tap the home key to return to the main menu. Open your device’s Phone app ​. At the top right, tap More . Tap Settings. Voicemail. You can: Change what handles your voicemails: Tap Advanced Service. Set up your voice mailbox: Tap Advanced Setup. Change your notification settings: Tap Notifications. Open the Google Voice app . At the top left, tap Menu Settings. In the Voicemail section, tap Voicemail greeting. Next to the greeting you want to use, tap More Set as active.

Shelby Doumitt of ServiceMark Telecom goes through step-by-step instructions on "How to Change Your Active Voicemail Greeting" on NEC DT800 and SV9100 Digita
When you first set up your Android phone, it may ask you to record your greeting for the caller. You can also keep the default greeting stored on the device. But, in future, if you want to customize the Voicemail greeting or want to create a new one, then you may need to delete the old recordings from Android. It may not be necessary depending on the Android device model & version; it’s good to know the process.