On PTASK table, when Assignment Group changes, automatically it should set back the State to "New"

[AbdurRahmanSnow]

Good afternoon.
Requirement is: On PTASK table, whenever we change the Assignment group and save the record, it should set back the state to "New", if the States are in Assess or Work In Progress.
1) I tried using Client Script, but it worked only on Front-end and after record saving, it again sets back the earlier state and gives an error message as below:
Invalid state transition. Can not update from state 'Assess' to state 'New' with given values.

2) I tried to create a new State Model for PTASK for "New" State but it does not change the State to "New", upon Assignment group change.
3) I also created a Business rule that sets back the PTASK State back from "New", "Assess" and "Work In Progress", to "New", upon Assignment group change, but this too, does not work.

It always gives me the above error.
Please help, as I tried but nothing works. I would be grateful for this.
@Ankur Bawiskar @Dr Atul G- LNG @Viraj Hudlikar 

[AbdurRahmanSnow]

@Ankur Bawiskar , please check. Really appreciate it. I would be very grateful. 

[Dr Atul G- LNG]

Hi @AbdurRahmanSnow 

Please check if there are any issues with the problem model that could be causing this problem. As you mentioned, it is a state model, which could be contributing to the issue. Also, try testing step by step and verify whether any Business Rules are running on this PRB task. Additionally, check how the behavior changes when the assignment is updated.

[Dr Atul G- LNG]

 I tried in my pdi and it is working as expcted mate... state not go to new state.

[AbdurRahmanSnow]

Hi @Dr Atul G- LNG 
Thank you for your reply.

If it is working the same, then what changes can we do so that, the State goes back to "New", upon Assignment group change?

[Dr Atul G- LNG]

But why do you want to change to new again? As per process, a team works on one task, and if you need another team to work, a separate task should be created—not the same task. Following the process, this would not be a valid use case.