Submitted a credit in 'Other Crew' (which is vague) on behalf of a friend and she's not comfortable having it listed and would like it removed. Can I do that?
Generally IMDb does not like to remove accurate information. Since it is an (uncredited) item, they might do so, but if they have evidence that is correct it is unlikely.
IMDb is a database of information, and what the person wishes to have listed or not listed is immaterial to the Data Managers.