Not sure but I think one or both of the following two queries should do your job
select (cast([1] as varchar)+'%') as Jan,cast([2] as varchar)+'%') as Feb
from StudentDiscountItem
pivot (
sum (conP) for mnameid in ([1],[2])) as t
where studentid=3575 And Sessionid='20152016';
If the above doesn't work, then try this
select cast(Jan as varchar)+'%' as Jan, cast(Feb as varchar)+'%' as Feb
from (
select [1] as Jan,[2] as Feb
from StudentDiscountItem
pivot (
sum (conP) for mnameid in ([1],[2])) as t
where studentid=3575 And Sessionid='20152016';
) as t
Hope, it helps :)