please explain the following code

       Dim rt As String =
"{\rtf1\ansi\ansicpg1252\deff0\deflang1033{\fonttbl{\f0\fswiss\fcharset0
Arial;}}\viewkind4\uc1\pard\qr\f0\fs20 "

when i change the font name int this line its reflected in crystal
report
but i cant change the font directly in creport. ie i can change it by
right click the field and format but i cat reflect on report

if i change in this line than only the font changed in report

wat can i do