Open Settings
and select Connection > SIP settings.
The Session Initiation Protocol (SIP) is used for creating, modifying, and terminating communications sessions, such as internet calls. SIP profiles include settings for these sessions. The SIP profile used by default for a communication session is underlined.
To create a SIP profile, select Options > New SIP profile > Use default profile, or Use existing profile to select an existing profile as the basis for the new profile. Use existing profile is only available when you have SIP profiles in your device.
To edit a SIP profile, scroll to it and select Edit.
To select the SIP profile you want to use by default for communications sessions, scroll to the profile and select Options > Default profile.
To delete a SIP profile, scroll to it and press C.
To delete a SIP profile, scroll to it and select Options > Delete.
SIP profiles may be preset in your device or you may receive them from your service provider, and you may not be able to edit or manage them.