whom

pronoun

1. (interrogative) What person or people; which person or people.
2. (relative) Used to refer to a previously mentioned person or people.“He's a person with whom I work. (defining)”
3. (fused relative, archaic outside set patterns) The person(s) whom; whomever.“To whom it may concern, all business of John Smith Ltd. has now been transferred to Floggitt & Runne.”