I have a client that I'm interviewing with for a potential project, however, after discussing we've decided to change the project type from hourly to a fixed rate.
Is this something they have to do on their end or is it possible that I can propose new terms/contract to them(even though I haven't worked with this client before)?
This will be the option on the client's end. Once they proceed with hiring you, they will have the option to choose if this will be an hourly or fixed-price contract. You can share this help article with them for more information.