BES Client installation on Linux and Unix Servers to non default directory like /opt/IBM/

How to install BES Client agent in Linux and Unix system to other
directory like /opt/IBM ,etc… other than default directory
/var/opt/BESClient Directory. The Linux RPM BES Client setup file does
not provide an option to install it on other directory that I’m aware

Please help if you have any idea…

This is typically achieved by leveraging symbolic links to redirect the default paths leveraged by the Agent to another filesystem or directory as desired.

As @Aram says you can use symbolic links between the default locations for the agent and a different directory.
You can create the links before installing or you can do it after by moving the directories and putting symbolic links in place.
In all cases the default directory locations must exist in the file system