QUES: He was appointed to the chair again in 1836 and held it until 1866 when he was to resign for a second time again on a matter of principle

correct the punctuation.

CORRECTED: He was appointed to the chair again in 1836 and held it until 1866 when he was to resign for a second time, again on a matter of principle.

QUES: Albergo AllAncora provides an outdoor terrace where you can comfortably eat and drink during the warm months

correct the punctuation.

CORRECTED: Albergo All'Ancora provides an outdoor terrace where you can comfortably eat and drink during the warm months.

QUES: For example if prolapse exists a surgeon can perform a triangular resection or chordal transfer depending on which leaflet is diseased

correct the punctuation.

CORRECTED:
For example, if prolapse exists, a surgeon can perform a triangular resection or chordal transfer, depending on which leaflet is diseased.