to remove or not to remove, that is the question

Expanding an existing carport do we remove the old slab and start fresh or keep it, retop and simply add new along the expanded edges? There is cracking at one corner. Also – do you provide a turned down edge along the side that is next to the house?
Thank you for your knowledge and insight.
Replies
Virginia
The crack is at a corner - and doesn't impact the general slab. Trying not to spend money unnecessarily or send materials to the dump without need.