@sureshp89882164 

you can use advanced script in field level WRITE ACL

I hope you know you should have security_admin role and how to create ACL

Something like this, please enhance if required

if (current.state.toString() == '101') { // '101' represents the 'New' state
    answer = true; // Allow write access for everyone in New state
} else {
    // Restrict to Assignment Group members or Global Problem Management role
    var user = gs.getUser();
    answer = user.isMemberOf(current.assignment_group) || gs.hasRole('problem_management_global');
}

If my response helped please mark it correct and close the thread so that it benefits future readers.