How can I change the indexed record to reflect the spouse instead of the mother.
This is a death and burial record for Johann Peter Kirsch. However the indexed record shows Johanna Friedericke Traub incorrectly as his mother. She is not his mother. She is his spouse.
That's a ...nicely mis-indexed record, aint it? The image is not available, so the index itself cannot be corrected, but you can get Source Linker to connect the index to the correct people, which is what you appear to have been actually stuck on, based on your screenshot.
To get back to Source Linker for this problem, go to Johann Peter's Sources tab and click "Unfinished Attachments" next to the source citation in question.
In Source Linker, first change the index focus person by clicking the "change" link/button in the left-hand column and choosing Johanna Friedericke. Next, change the tree focus person by clicking "change" in the right-hand column and choosing Johanna Friedericke Traub. Then click "Compare" and "Attach".
You'll notice that Source Linker will be unhappy about the attachment to Johann Peter, marking it with a black triangle-and-exclamation, but you can simply ignore this. There is no way to make Source Linker fully happy when the index's relationships are incorrect.1