Article 20 GeneralI1

The times or periods prescribed by these Rules for doing any act or taking any proceedings thereunder may be extended or shortened by the Comptroller if he thinks fit, upon such notice and upon such terms as he may direct, and an extension may be granted although the time for doing such act or taking such proceedings has already expired.

Where the last day for the doing of any act falls on a day on which the Patent Office is closed and by reason thereof the act cannot be done on that day, it may be done on the next day on which the Office is open.