Transport Request

hi ,

Please clarify my doubt regarding Transport Requests.

I have made changes in the Delivery Class of a Z table and for this I created a TR.But later,I want to rollback my changes which I have done and also I want to delete my TR.

When I tried to delete Transport Request ,a message is coming that,

" Request could not be deleted as the object is locked".

How to delete the TR in se10 and how to make the changes rollback?

Thanks in Advance

mvk