Hi Lena,
I was not even aware that this can occur and looking at my own listing I can't even see the possibilities of guest changing times.
I however occasionally had guests ask through the messaging on the platform if they can check in early than my 4:00 usually I can accommodate them though rarely had to decline.
I wish I could give you more advice and will be following to see what others say about this.
Thanks for bringing this up.
Bettye