Preferred Seat change

[purpleparrot]

I am flying SIN to SFO in August this year in Y. Today I received an email from Singapore Airlines telling me that they had to change my preferred seat from 47B to 47H on the basis of "flight changes" being seasonal schedule changes or aircraft changes. From what I can see neither he schedule or aircraft has changed.

Is there another reason why I have been moved seats? I don't really want to sit in 47H as it's the aisle seat next to the WCs and a bassinet seat.