In cases of severe travel disruptions, I have had Advance tickets endorsed for travel the day after. In practice, an employee at a staffed railway station wrote and stamped something on the back of my ticket. Then I travelled the day after.
Is this endorsement necessary? For example, for todays disruption the message says:
If customers want to change their journey, tickets for travel today can be used tomorrow providing you begin your journey before 14:00.
You may use your ticket on London Midland, CrossCountry, TransPennine Express and Arriva Trains Wales via any reasonable route.
Does that mean an endorsement is redundant? Then what is the point of an endorsement at all?
If it’s announced (which is usually only the case during wide-reaching, extreme disruption) that tickets will be accepted the following day, then you will not need an endorsement. After all, they often want to discourage people from travelling at all on the affected days, so requiring you to go to the station and get an endorsement would defeat the whole purpose!
In this case, no, the endorsement shouldn’t be necessary; but many members of staff will give you it anyway to give you peace of mind and avoid any potential arguments with staff who might not have heard about the easement.
If no such blanket easement is announced by your train operator, though, I would always recommend getting an endorsement (if they’ll give you one!).
Bear in mind as well that if your journey requires travelling on other operators’ trains, they will also need to have announced an easement, unless your ticket is valid on other days. This is another possible reason for you getting an endorsement.