Decks, Patios, Porches and Docks - Porch Overhang Sagging

I have a large porch with two support poles on the overhang. In the center of the overhang at the seam there is a slight sagging. The house was built in 1978. I plan to hire someone to fix this. Just wondering if this is a major expense or can this be fixed somewhat reasonable? Is it possible to just replace the outside wood that runs along the length on the outside? Does this require replacing both support poles? The overhang is about 15 feet in length by about 6 feet in width. The house was built on a land fill in 1978 and I know the land and house has probably settled. It only seems to be sagging right at the tip of the front where the seam is on the outside board that runs along the outside. Any advice would be appreciated.

Can someone please answer my question about Porch overhang. Thanks

Your description of the problem is confusing which I think is why no one responded...

But if I am understanding correctly and you are having a 'sag' where there is a 'seam', then the problem is the 'seam' which should not be there in the first place.

Sounds like you have a 15-ft span between porch columns. Not sure how settling would affect a point between the columns rather than at one of them. But if the porch roof support member is not a single beam, then it will sag at the joint, unless you put another column at the joint. You need to either replace the beam or install another column.

Or tear out the porch roof and do it right.