Earlier today booked a first class advance for my partner from Rickmansworth to Middlesbrough arriving at Darlington at 2119hrs and then a Northern service from Darlington to Middlesborough returning. Just learnt that Northern are likely to be on strike, What options exist, I have not yet collected the tickets, could the ticket be endorsed to take an earlier train and change at York for the last TPE train of the day to Middlesbrough, am are right in assuming that a taxi would be at one's own expense as it is a strike.