Joining 2 rings together can it be done.

[readingisallowed]

After an operation on my arm a few years ago my wedding and engagement rings no longer fit.
I kept hoping my arm and hand would go back to normal.
These are size k and I think I'll need a size n. Not sure they can be resized.
I am wondering if they can be redesigned to size n joining them together.
Both are 9ct gold. Wedding ring has a pattern and the engagement ring is plain with a diamond.

If you show them to a reputable jeweller they will be able to do it, sure. They can add a bit more to the band so it will fit.

DH’s wedding ring wore very thin at the bottom, so he had it remade, using his father’s ring as well as the original.

Do you mean soldering them together to form one ring (easily doable), or melting them down to make a new ring which is size N? That could be trickier. Your best bet is to take them to an independent jeweller (not a high street store), and see what they advise.

My sister did this with 3 wedding rings (same husband, she just had 3 wedding rings). They were melted down and re-formed into a ring of her design. They had to go through assay to get the gold content confirmed. Cost a few hundred pounds.
you would need the stones and settings removed of course, although the stone could be reset.