You do not need a finished scheme. A room, two colour ideas and the things you are unsure about are enough to begin. Your envelope becomes a local note you can keep and change.
Bring a little context.
The room
Describe the part you want to change and the surfaces you plan to keep. A simple sketch is often more useful than a perfect description.
The light
Notice a bright moment and a dim one. Include artificial lighting, nearby colours and anything reflected in the surface.
The meeting points
List corners, shelves, sockets and adjoining finishes. They affect how a colour becomes a finished surface.
Your material conversation.
Use the glaze names as a shared starting point. Physical samples and the final specification can follow.
Still finding your colours?
There is no need to settle everything in one sitting.