In Acrobits Softphone, the menu button is your friend. If you are on a screen where you think you should be able to do something, but can't figure it out, try pushing the menu button. This is especially important to users who previously used an iPhone, since they won't be used to using a menu button.
Important uses for the menu button.
Keypad - Press menu to exit or hide the app. Also, press menu to access the settings.
SIP Settings Screen - On the screen that contains your basic SIP settings (username, password, domain, etc.), press menu to delete or disable the account.
SIP Log - When reviewing the SIP Log, press menu to move to a certain point in the log or save the log somewhere on your device.
Call History - Tap on Menu to clear the history
Call Details - Tap on Menu to delete the individual call from the history.