Can alert sounds on iPECS app on iPhone be changed?

[MattJackson]

I have installed an iPECS system and multiple users are soft-phone only using the iPECS ONE app on their iPhones. It's very obvious where to change the ringtone, but when the user has an alert on their iPhone it also makes a notification sound, and this sound is a 'ding-dong' like a doorbell.

Is there a way to change this either via the app itself or via iPECS web login? I've searched high and low and can't find it.