I don't like your boss's way of thinking. It's so rude to foreign people. But if you need... The common Japanese kanji which has "za" sound is only one. It's 座(seat, place, position, theater...). "Li" has comparatively many kanjis on the other hand. Please choose as you like. 理座 the place of principle 利座 the place of benefit 李座 the place of plum 莉座 the place of jasmine 梨座 the place of pear 璃座 the place of lapis lazuli 麗座 the place of beauty 狸座 the place of raccoon dog (↑ I think it's kawaii the most) http://jisho.org/search/り

座　This Kanji pronuncation is ”ザ” 星座　"seiza" mean constellation. you can find your Kanji name!

Just put kangji that has the same pronounciation to your name. For example, 理紗 is pronounced as lisa. However , 濁音(voiced sound) is marely used for japanese name. It may be difficult to find appropriate kanji for "ザ".