Hi Venu,
Why your saying about Right side fields to move left side? Left side fields which are in blue color not modifiable.
at left side which are fields are available those are part of your data source and visible at RSA6.
Un available fields at RSA6 and un hided(by seeing table ROOSFIELD) those if you seen them at Right side(i.e comm str) then only you can move from right to left side.
Thanks