Any changes in policy need to go through the agent. They need to endorse your request form.
By the way, I am on AIA HSG Max A + Max Vitalhealth A Value rider. I think this is the best compromise that allows private hospital claims while not blowing the premiums to the roof like Max Vitalhealth A (without the Value). There is a risk that the public/restructured hospital can only arrange specialist appointments weeks later, so I want the option of the private hospital for really emergency case (same day or next day).
I don't have children, but my guess is only accident insurance is really necessary. For an upgrade, then the IHS is next step, which I feel that Great Eastern Supremehealth (P Plus) alone is the best because the premiums are really low if no claims. If your children have no genetic disorders, then looks like no claims for many years, then you want really low premiums until the children start working.