こちら、 そちら、 あちら、 どちら

You can’t use これ, それ, and あれ to refer a person. Instead you use こちら, そちら or あちら. The Japanese equivalents to the English “this” “that” and “who” are こちら、そちら、あちら and どちら. These are used in formal contexts.
These also indicate direction.

トイレは どちらですか? Where is the washroom?

トイレは こちらです。 The washroom is this way.

きょうしつは そちらです。 The classroom is there. (that way)

たなかさんの レストランは あちらです。 Mr.Tanaka’s restaurant is over there.

こちら, そちら, あちら and どちら are used to refer a person in a polite way so we often hear these expressions in business situations.

こちらは このレストランの シェフです。 This (person) is this restaurant’s chef.

そちらどちらさまですか? Who is that (person)?

あちらは New Tokyoの しゃちょうです。 That is the president of “New Tokyo”.
-Note-
When it refers to a person, it is better to add さま after どちら to say
“who”. It is more polite than どなた and だれ.
+ polite どちらさま > どなた > だれ
It can also be used to ask for the name of organisations to which they
belong to.
Exemples:
だいがくは どちらですか? Which university do you study at?

かいしゃは どちらですか? Who do you work for?