A. This is a common enough exercise in any organisation and there is no reason why schools should be any different. There is bound to be the kind of anxiety that change of any kind can produce. What is most important is that the entire process should be characterised by openness, consultation and dialogue. What causes the greatest stress is secrecy and the feeling that there is a hidden agenda known only to a select few.
Your rights are those of any employee. You have a contract which specifies the post you occupy and the level of remuneration to which you are entitled. Your conditions of service are set out in the School Teachers' Pay and Conditions Document. The latter cannot be changed and the former can be altered by mutual agreement. What your contract probably does not specify is your job description and this is not unreasonable, because most jobs need to evolve and adapt to changing circumstances.
If what is being planned is a review of duties and responsibilities, one would hope that this would be achieved through a process of consultation and dialogue, with outcomes acceptable to all concerned.
If, however, there is an intention to remove some posts and create new ones, unless this, too, can be achieved by agreement, there may be the possibility of redundancies and you are right to be worried. Your rights in this case include the right to be informed of what is happening and the right to the protection afforded by employment legislation. That legislation does not give you a right to a job, but it at least ensures that you do not lose it without proper procedure being followed and appropriate compensation being paid.
What you need to do immediately is to seek a discussion with your head, in the hope that the situation will be clarified. If the outcome is unsatisfactory, or if there are plans which may involve redundancy, you should consult your professional association without delay.