Delete Change Request FROM SM

Dear All,

i am having SM 9.30 & Database is Oracle 11G, we have so many chnage request which we dont want and i want to delet this chnage request from SM. can you help me how can i delete this chnage request from SM only,  is ther any impact of this Chnage deletion

after deleting when i am generating report it should not come in resport

 

NEED YOUR HELP 

THANKS

KOMBOO