I have created a community site where I provided an inbound new guest appointment flow which is working fine.
Now I want to provide a flow to modify or cancel an appointment on the same site. But the flow is not working. 
What is the solution for this?
Your guidance will be very helpful.

Thanks
 

Hi,
I have created an EmailMessage, but I cannot fetch the name of the attachments through "EmailMessage.Attachments", so how? Any examples?