You may be able to, but the problem is, if something goes awry, and the password doesn't change properly, you may lock yourself out of the WiFi, which would then necessitate a LAN cable connectible device to remedy. Also, the second you click Save Settings, you're going to be kicked off of the WiFi network, and you'll have to enter the new password in your device to reconnect. But, again, if something goes awry. This is why it's recommended to perform any WiFi settings changes with a LAN cable connected device.
To access and change the network password(s), please see "How do I manage my built in WiFi modem?" in this PDF.
Again, this should be done with a LAN cable connected device for the reasons mentioned above. Perhaps you have a friend or relative from whom you could borrow a laptop with LAN cable connection ability.
If you do decide to try this with a WiFi device, make sure you write down the new password, as it would be awful if you changed it, got kicked off of the WiFi network, then went to enter the new password in your device in order to reconnect, but you couldn't remember what it was.
~~~ Or, if you have one device that can connect to the 2.4Ghz radio and one that can connect to the 5Ghz radio, use the first to change the password for the 5Ghz radio. Then enter the new password in the 5Ghz connectible device, and then connect with it. If it connects, then proceed to use that 5Ghz connected device to change the 2.4Ghz password. Then enter the new 2.4Ghz password in the 2.4Ghz connectible device, and then connect with it. This way, you always have one device that you are still connected with and you eliminate the possibility of locking yourself out completely. And you can use the same password for both radios (2.4Ghz and 5Ghz), or use a different one for each.
Again, though, and for the third time, it's recommended to perform any changes to the WiFi settings with a LAN cable connected device and not a device that's connected via WiFi.
Lastly, and only because the instructions above are NOT the recommended method(s) for changing WiFi settings, I have to say that I am not a HughesNet employee. I'm only a longtime customer.