How to Pass the variables from one Procedure to Another Procedure with OUTPUT Parameter
Here is the Example:
Step 1: Create a Table 
CREATE TABLE  StudentsDetails
(
    [Studentid] [int] IDENTITY(1,1) NOT NULL,
    [Firstname] [nvarchar](200) NOT  NULL,
    [Lastname] [nvarchar](200)  NULL,
    [Email] [nvarchar](100)  NULL
)
Insert into StudentsDetails (Firstname, lastname, Email)
 Values('Vagalla', 'Suresh', 'vagalla.suresh@gmail.com')
Insert into StudentsDetails (Firstname, lastname, Email)
 Values('vagalla', 'Saran', 'vagalla.Saran@gmail.com')
Insert into StudentsDetails (Firstname, lastname, Email)
 Values('Rajesh', 'Kumar', 'Raj.Kumar@gmail.com')
Insert into StudentsDetails (Firstname, lastname, Email)
 Values('Prasad', 'Reddy', 'Prasad.reddy@gmail.com')
Insert into StudentsDetails (Firstname, lastname, Email)
 Values('Sukanya', 'reddy', 'Sukanya.reddy@gmail.com')
 select * from StudentsDetails
Step 2:
Declare the Parameters.
As of my concern, StudentID is the Input value and Expecting 3 output  values.
create  procedure GetStudentDetailsWithID
(
@studentid INT,        --Input parameter ,  Studentid 
@studentFirstName VARCHAR (200) OUTPUT,  -- Output parameter of student Firsst name
@studentLastName VARCHAR (200) OUTPUT,  -- Output parameter of student Last name
@StudentEmail VARCHAR (200) OUTPUT   -- Output Parameter of student email Address
)
AS
/*=====================================================================================================
   With one input value, getting full details of the Student
=====================================================================================================*/
BEGIN
SELECT @studentFirstName = Firstname, 
  @studentLastName = Lastname, 
  @StudentEmail = email 
  FROM StudentsDetails 
  WHERE StudentID = @studentid
END
Step 3:
Now I am trying to get the Final result 
Create procedure ReturnFullData(@studentid int)
as
/*=====================================================================================================
   With one input value, getting full details of the Student
=====================================================================================================*/
begin
Declare @studentFName as nvarchar(200)   -- Declare a variable to get studentFirstName
Declare @studentLName as nvarchar(50)     -- Declare a variable to get studentLastName
Declare @StudentEML as nvarchar(50)     -- Declare a variable to get Studentemail
Execute GetStudentDetailsWithID 1 , @studentFirstName = @studentFName output,  @studentLastName = @studentLName output, @StudentEmail = @StudentEML output
select @studentFName as FirstName,@studentLName as LastName ,@StudentEML   as Email   -- "Select" Statement is used to show the output from Procedure
end
-- here is your Fina output
exec ReturnFullData 1
 
