Does anyone know how Amex handles partial refunds with regards to the $200 credit?

My situation:

- Prepaid a hotel in December for $600
- got the $200 credit in December
- wife has covid so have to cancel the booking this weekend. The cancelation rate is 50% inside one week.

So assuming the hotel puts $300 back on my card, ho does that work with regards to the credit?

I could see an argument made for a full clawback or none at all. Anyone know? Thanks