In exceptional circumstances, a Greece Visit Visa may be extended beyond the initially permitted stay. Extensions are typically granted only on humanitarian grounds, due to reasons of force majeure, or in cases of serious personal emergencies. An extension must be applied for before the current visa expires and is subject to approval by the relevant Greek immigration authorities. Extensions are not granted for general tourism purposes, and overstaying your visa without prior approval is a serious violation that can have long-term consequences on your future Schengen visa applications.