To launch an over the air command, you can use AT commands and telnet into the modem

The command is AT*PROVISION  

Be very careful as if the OTA fails (due to coverage issues or account issues, etc) 
the modem might be rendered offline and this would require the visit to the site.  

Also, resetting the modem remotely should (if the carrier network is acting properly)
registered with the right IP after a reset.