Recently i have a faced one issue where i required to change TR status from released to unreleased.
I have assumption that once we released TR(task) then we can not revert TR to modiable, but that was wrong.
SAP have provided program using which we can do this.
Initially TR was in Released status.
Step 1: Go to SE38-> enter program name : RDDIT076 -> execute
Step 2: Enter TR/Task which status you want to convert from released to modifiable -> execute program
Step 3: you will find TR with R (Released) status.
double click on R status(encircled in above screen), you will find below screen where need to edit R status to D status(D= Modified).
click on Save. -> exit from program
Step 4: go to Se01-> enter TR name, you will find TR in unreleased(modifiable) status.