What is the difference between 做番 vs. 做返? A friend (Mainland Chinese, living in Hong Kong) recently posted the following sentence on Facebook:


  聖誕節買禮物?做番中國人啦!


As I had never seen the "做番" construction before, I asked if perhaps she had mistyped the phrase, and had wanted to use "做返" instead, seeing as the pinyin would be the same for both. 

She responded that, in this case, both were OK. 

Is her assessment accurate? Why would one use "做番" instead of "做返"? Is there a subtle difference in meaning?
Both 做番 and 做返 are used to represent the Cantonese expression, jouh fāan.

There is a reason why some people choose to write 番 and others write 返.  Etymologically speaking, 返 is the correct character to use.  However, because the traditional literary pronunciation of 返 is fáan (2nd tone) instead of fāan (1st tone), some people will write 番 instead to make it explicitly clear that the 1st tone reading is intended (even though the original usage of 番 has nothing to do with 返).

Because written Cantonese is not standardized, both characters are typically seen; so your friend is not wrong when she said that both are okay.

BTW, the reason why 返 came to be pronounced in the 1st tone rather than its traditional 2nd tone is most likely due to changed tones, a phenomenon that affects various words in Cantonese (this phenomenon somewhat analogous to how erhua affects various words in Mandarin).