What compost should I use to repot my new dragon tree?

United Kingdom

I have recently purchased a dragon tree. I belive the conditions in my hallway (where it will be situated) are good. However, I have bought a new pot for it to sit in and I wondered What sort of compost I should use to re pot it? I have recently potted a rhododendron and bought the compost suitable for this. My partner says that we should use the remaining compst for the dragon tree but I am concerned that they may thrive in different types of compost. Please help!

On plant Dracaena marginata