I have a valid super saver ticket between Thun and Zurich.
Due to personal reason, I should depart from Spiez instead of Thun.
Hence, I need additional ticket from Spiez to Thun. Can I buy the libero extension ticket (Thun: zone 700) to cover additional 2 zones(701, 720) till spiez? or should I buy the libero individual ticket?