shell script/utility replace 2 byte unicode in binary file

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http://unix.stackexchange.com – I have many large Unicode files. I would like to replace each Unicode byte pair with a new Unicode byte pair. For example, the original file contains "C3 B9 C3 AB C3 B8 C3 B0" and I would like to replace this with "D7 A0 D7 A8 D7 9B D7 A9". I would need to replace every "C3 B9" with "D7 A0" throughout the file. There will be about 30 different "C3 XX" values to be replaced by "D7 YY" values. I would need a table to loop through for each replacement. Ideally this would replace the original file but it can also create a new output file. Is there a utility that runs under Ubuntu that will do (HowTos)