If your modem is hard whired to use a given network, then, you can't change it.
Exploring the "consumer" part of the Huawei site, the modems and network adaptors they offer don't look like they can use any SIM card. It all depends on the device those are connected to.

Most modems are NOT set to any provider or network. It only depend on the settings and configuration.

The exeptions are normaly cable and satellite "modem" that are factory set and can only be configured by a technitian of the provider.

Electro
October 2014