Change availability hours for a specific day?

Hi all! Is there any way to change availability hours for a specific day without affecting the other occurances of that day? For example, on Saturdays I am generally free from 3pm-11:30pm. However on Saturday January 26th I have plans at night. I'd like to change my availability for ONLY THAT SATURDAY from 3pm-7pm, but not for every Saturday. It seems there is only a capability to change it overall, not on certain days. Can anyone help?

 

Thanks!