Check FP availability at different park before cancelling FPs?

[MouseMum]

A very successful night was had by moi in getting all the FPs and times wanted. Yay for me! Now, just 36 hours later, I discover that a family member who I haven't seen in a very long time will be visiting WDW. Naturally, we want to get together. I'd like to switch FPs for one of my days to another park. Can I see what FPs are available in HS without cancelling my current MK FPs?