If, at any time before or during the construction
of the required improvements, it is demonstrated to the satisfaction
of the Planning Board that unforeseen conditions make it necessary
to modify the location or design of such improvements, the Board may
authorize such modifications upon written request to the subdivider,
provided that such modifications are within the spirit and intent
of the Board's approval and the purpose of these regulations. Copies
of the authorized modification shall be made part of the official
record of the Board.