Quick question
You can replace runes in armor regardless of whether or not they’re salvageable; the new rune will overwrite the old one. You just won’t be able to get the old one out if you don’t take them out before putting in new ones.
that karma armor is not salvageable . so you won’t get any runes out of it unless you use an extractor . keep that in mind when putting new runes in the karma set .
any ways . runes or sigils can be put into any used slot . it over-wrights the old one and you get a caution message showing what the new item will be something like “warning : existing upgrade will be destroyed”