You can no longer change partner reward flights?

I booked a starlux flight to fukuoka, decided I want to visit another city instead, tried to change on the website throws and error

So I called in to Alaska line, the lady told me you can’t change it and I’d have to cancel the original flight and rebook

Problem is there’s a non refundable partner booking fee and I’d rather not eat that…

I was able to change my flight last year with starlux via Alaska website, the lady said this got changed recently, and you can’t change partner rewards flight now

Anyone aware of this? Is this true? I looked up this sub but don’t see anyone mentioning this