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1) Whom should I report to?

2) Who should I report to?

Which one is correct and why?

/Sameer
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askshameer1) Whom should I report to?

2) Who should I report to?

Which one is correct and why?

/Sameer

All of the following are correct. I have marked (<<<) the one which is most often used.

To whom should I report?
Whom should I report to?
Who should I report to?
<<<

CJ
Comments  
1. Whom should I report to is correct.

You use "whom" when it involves an objective pronoun and "who" when it involves a subjective pronoun.

Example:

1. Whom should I report to?
A: I should report to him.
-"him" is an objective pronoun so you use "whom".

2. Who bought the shirt?
A: He bought the shirt.
-"he" is a subjective pronoun so you use "who".

According to wikipedia:
"The English language subjective pronouns are I , you , he , she , it , we , what , who , and they . With the exception of you, it, and what, and in informal speech who, the objective pronouns are different i.e. me, him, her, us, whom and them."
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1) Whom should I report to?
2) Who should I report to?
What Gilysse wrote is correct.
However, 'Who should I report to?' is not grammatcally wrong.
BUT it should be 'To whom should I report?'
1) Whom should I report to? 
2) Who should I report to?
What  Gilysse wrote is correct.
However, 'Who should I report to?' is not grammatically wrong.
BUT it should be 'To whom should I report?' 
 CalifJim's reply was promoted to an answer.
Students: We have free audio pronunciation exercises.

Whom should I report to?

Neither. The correct answer is "To whom should I report?"