[QA] How to reject model state?

Hi @fahad19 can you example me how to reject `todo` state when get error from server?

for example use-case:
- i see todo `Hello todo`
- i click edit todo label `Hello todo`.
- i type new todo label `New todo`.
- i submit todo to server for save.
- server return error 500/400 for me.
- i should see previous todo label `Hello todo`.

How i can reject todo label to previous state?

Thanks.