Chapter 1 of Part 15 of the Principal Act is hereby amended -
(a) in section 465, by the substitution, in each place where it occurs, of "18 years" for "16 years" in paragraphs (a) and (b) of subsection (1) and paragraph (a) of subsection (2), and
(b) in section 469, by the substitution in subsection (1), in the definition of "dependant", of "18 years" for "16 years" in each place where it occurs.