SAP Tables

i have modified some existing tables like ekko,ekpo in my system. now i want to restore the default data. is there any chance?

no way, only way re-installation

if u added any append structures, those can removed manually.
process: se11->table name-> click on append-> select ur structure->
delete those fields one by one -> save and activate -> back
se11-> give structure name -> click on delete
se11-> table name -> activate

hi..

in SAP standard tables u cant add fields directly...only way is append structure...and as said above...delete fields from append structure accordingly...if still some doubt is there...do version comparison