Entryway addition question

[Robert Macejak]

Good Evening, My wife and I just purchased our first home that was built in 1973 with a 6' addition to the front of the house put on more recently. They used a thicker rebar in the addition so the floor has a slope to meet up with the rest of the home. We want to make it a raised portion with a step down into the living room. Is this a DIY'able project or do I need to call someone in? I believe we would also have to raise the door frame to make it match as well.