I am calling with regard to my request for information .

[scott833]

1) I am calling with regard to my request for the information regarding the date of which I join and left the school.
2) I am calling regarding the information that i requested. I have requested the information about the date of which i join and left the school.

 

[Rover_KE]

I think you mean

'I am calling about my request for the dates when I joined and left the school'.

Rover