Hi,
Someone should update your support team:
From: support@meraki.com
To: charlie.rhodes@alfalaval.com
Subject: RE: Cisco Meraki Case 04413769: MX64 Remote WAN IP change [ ref:_00D606uBw._5000d1Wtbj1:ref ]
Greetings Charlie,
That would be possible remotely via dashboard, as long as you have a valid static IP for the uplink.