Difference between End function and Exit function ?

what's different between End function and Exit function ?

 

Thanks a lot!
i'm writing a simple application by VB and there is a fault. I appreciate any help.
in my code i use a function :
Private Function HexString(ByVal EvalString As String) As String
......
end function

and i call it for specified purpose :
......
s = HexString( Byval EvalString As string)
.....
but the VB warms me an error "expression expected" @ Byval . i don't know how to correct it

 

i solved the case. the call function should be :
......
Dim ss As String
ss = HexString(s)
......