how can i restirct user not to take back an issue in workflow, mean once it is moved from ToDo to InProgress then it should not allow anyone to revert it back???

[Nic Brough -Adaptavist-]

Remove the transition from the workflow, or add conditions to it to prevent it.

[Sten Sundelin]

You may still want to have a small set of users or groups being able to do this if something unexpected happens and/or priorities change.