Hi,
Assuming you have configured deleting change request properly....
To check if a request is still in changelog:
1. DSO/Manage
2. Choose a request to check here:
3. Go to contents / change log
4. paste request no here
if you find a request here it mean the request wasn't deleted.
You can check it in DB02 too.
Requests can be check in SE16/RSTSODSREQUEST
Regards, Leszek