You can do so by logging in to your carrier’s website or contacting customer service for assistance. Some network providers also let you do so via their mobile app. Go to Settings → Phone → Change Voicemail Password.Enter the new password.
Hello! Thanks for calling [LinkedPhone’s Customer Success Team]. We are currently helping other customers achieve their goals and want to do the same for you! Please leave a message with your name, number, and a brief description of how we can serve you. We promise to return your call [before close of business today]. In the interim, you can also check out our website at [linkedphone.com] for helpful answers to our most common requests. Thank you.

To force close Phone, on iPhone X and later swipe up until you see the apps in task view, then swipe up again on Phone. On iPhone 8 and earlier double press the home button, then swipe up on Phone. You will see all the open app cards.
In sales, immediate communication with your prospects and current customers is important. Being available to answer questions or further negotiate a deal allows your clients to feel secure and more apt to purchase from you. But what if you can’t answer the phone when they call? Make sure you have a voicemail system set up so your clients have the opportunity to leave you a message.