To change the call format on your device, you need to go to your device's settings and locate the "Call" or "Phone" option. From there, you can select "Call settings" or "Incoming call settings," depending on your device. You may have the option to change the call format to a different type, such as HD Voice or VoLTE (Voice over LTE). If you have a smartphone, you may also be able to select an app for making calls, such as WhatsApp or Skype. Keep in mind that some call formats may require additional features or services, such as a compatible network or plan. It's important to note that the specific steps to change the call format may vary depending on your device and operating system.