Dear Subbarao Narne.
As you already know, Mass Change transactions of RE-FX is just for Responsibility , Organizational Assignment and Update Objects.
So, If you want to mass change the VIBDRO-XMETXT field as description, you can consider 2-options;
1) Use function module : You can use this function in the LSMW.
- API_RE_RO_CHANGE or BAPI_RE_RO_CHANGE (BUS1504_CHANGE)
2) Direct Changes on the table list (Not recommend)
- Case of your requirement field as VIBDRO-XMETXT is not key field, so even if you try to change
this filed by changing of direct table list , Actually, that is no problem~ 
(But this method is not recommended)
Regards,
Jeong, Yeong-Chul.