Airports don't "reallign" their runways - that would imply moving the runway, which tends to be a big task.
Much easier to just re-number the runway, and that's exactly what is done.
Someone who has been around aviation for longer than me will be able to confirm that the runway numbers at Heathrow were changed, not all that long ago. Can't actually remember what they were changed from, though? I have a feeling they used to be 28/10 (it was either that, or 26/08) until not-so-long-ago-that-there-are-still-people-around-who-remember.
FFF
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