Apologies for the late update!

So I ended up calling the Enrich Hotel Concierge Hotline that was provided in the email with the booking confirmation. After a brief explanation of my situation, the person on the other side of the call was quite understanding.
He explained that usually it is not possible to directly cancel or change a reservation as it is done by another provider (Rocketmiles/Rocket Travel site if I recall correctly).
However, it is possible to send in a modification request to them, which would require approximately 3-5 business days. After that they would inform me on whether or not my request has been approved.

Luckily, it was approved and I was able to change it to my new departure date.

Hope that clears it up and can help someone in the future.