endianness - Can Endianess of system be changed using c code -

i know endianess little or big inherent system. then, how possible change using c code, have seen code, says can change endianess.

endianess depends on cpu hardware. can't it.

the code have seen tossing bytes around 1 endianess other. though cpus (for example powerpc) have possibility configure endianess writes hardware register.