When to use "le" as you?

Hola! Can anyone help me with the usage for "le" as you? For instance: ¿En qué le puedo ayudar? (How can I help you?) I realize this is probably a rookie question, but why wouldn't you use tu or usted?

I think that in the sentence you quoted, "le" is an indirect object pronoun. As you may know, in Spanish object pronouns are placed in front of the conjugated verb. I am still working at recognizing and understanding how various pronouns work, so if I am wrong hopefully one of the more advanced students will correct me and inform you accurately.

Thank you Dan! I'm still adjusting to the sentence structure.

Hola amigos, Brian, Dan's reply is correct, "le" is an indirect object pronoun. The sentence structure will come to be natural to you in time. ¡Te prometo! Saludos, Ricardo

¡Me encanta cuando estoy correcto!

Hola Dan, ¡A mi también! A propósito, creo que es más común decir "tengo razón" en vez de "estoy correcto". Saludos, Ricardo