How Can I delete override( regions ,Lines , Polylines) in AutoCad ?

Unfortunately there are no other option rather than overkill  in my knowledge 

I Tried Overkill with these options but not working especially with regions.

I think overkill is good command...

select this 

than click delete

Select these lines which you want to delete and right click on it and choose the delete option.

Type a command trim(tr) Select objects or <select all> 

Select object to trim or shift-select to extend or

You can use the Overkill command.this command deletes the duplicate objects and combine the overlapping line and arc

s. 

mostly i can use trim or select object and delete