Need update lastest FW. How I can do that? Operator change software and not possible connect anymore. 
RB953GS-5Hnt
OS 6.49.4 (stable)
use USB Adapter connected to Windows machine.
Use a proper device from vendor to update firmware.
If his device suport some of FOTA update by e.g. FWLOAD commands then read manual of firmware and share the steps, then we can help.
Just in case, here it goes the link to commands for the modem - http://download-c.huawei.com/download/downloadCenter?downloadId=99395