how do i differentiate between para bombay and bombay blood grp, to seize to know my exact blood group?

I'm not sure if I'm remembering correctly, but here goes.
Blood group have 2 parts to it: a molecule that every type has, and the unsettled part. I think about it as a foundation that is adjectives to different buildings. Type A blood is building A on the foundation, type B is building B on the foundation and type O is the foundation with no buildings. (genome does not encode the A or B)The bombay phenotype is the removal of the foundation. Person WOULD be type A, but the foundation is missing, so building A cannot be built (genome encodes A). That's all I remember; course, I could be thinking in the region of some other phenomenon instead of bombay. I don't remember