At times decoupling transport from a Change Request in ChaRM gives error. A useful workaround is to decouple it from Solution Manager.
The steps are listed as below
1. Execute transaction /nSOLAR_PROJECT_ADMIN in Solution Manager system.
2. Select the project to which the Change Request belongs to.
3. Click on tab “System Landscape” and then “Change Management”.
4. Click on “Show task List”.
5. Expand the task list and under the development system, there is a the task “Decouple Transport Request”.
6. Execute the task. It will give the list of transports under that project.
7. Select the transport request that needs to be decoupled, and click on ok.
8. The transport request has now been decoupled from the ChaRM change request. Refresh the ChaRM CR and the transport will no longer be visible under Transport Management.