you can maintain the column's list in dtaabase and fetch with the help of additional parameter (says reportID ) in stored proc. see below

table defintion (ColumnID, ColumnName , reportID)

table will have

1, 'EmpName' , 45 (reportID)

2, 'salary' , 45

etc

So NOw with the help of additional param in SP , you cna retrieve the column list and use in your dynamically.

column addition can be done in above whenever developer ask