How would I change a will after the testator dies if the family agrees to different terms would this need to be done via a solicitor or can it be okay as long as we all sign something?

You cannot make any changes to a testator's will. A person's last will and testament is one of the most respected and revered documents in law and has been so for thousands of years. In it, the testator directs the distribution of their own property after their death. As long as the will is technically valid in its jurisdiction, the provisions in the will must be followed. You cannot change someone's will after they die, no matter what the family agrees to.