CDO

Hi all,
I am having trouble replacing variable using cdo in netcdf file. I get the following error message:
cdo replace: Variable wind (code -1) not found!
I am sure that the variable 'wind' is there in the source file but in the destination file the variable name is written in caps format as 'WIND', does that make a difference? The variable description retrieved using ncl_filedump in source file is as below:
float wind ( time, lat, lon )
_FillValue : -9.99e+08

The variable description in destination file is:
float WIND ( time, lat, lon )
long_name : wind at the lowest atm level (WIND)
units : m/s
mode : time-dependent

Are there other options to replace variables? Please help.

Thank you,

-Sagar