How to deleted released change request

1. Table E070 store status:

D Modifiable
L Modifiable, Protected
O Release Started
R Released
N Released (with Import Protection for Repaired Objects)

Sample coding:

UPDATE E070
SET TRSTATUS = 'D'
WHERE TRKORR = 'PI6K000595'.

If you have authorization, you could simply do the following:

SE03-> Unlock Objects (Expert Tool) to do the same job for all entries in particular TR

2. Cannot delete (request locks still exist) 

Contact your system administrator, who must ensure that the request locks (table TLOCK) correspond to the locked objects in your request.