A Kinessi is akin to being the ward of a House. The Kinessi is considered in the care and protection of the House they are hosted by, but they retain their last name and familial connections. In every other functional way they are considered a member of their host house.

How does one become a Kinessi of another House?
You can become a Kinessi when your HoH and the HoH of the house you are moving in to agree on the arrangement. Circumstances where one becomes a Kinessi are unusual and generally revolve around House Alliances, or in some cases as a result of the end of a war.

What is my name if I become a Kinessi?
You keep your name! The only difference is that you are given the title Kinessi of House <New House>. So for instance if Elexia Marindur were to join House Serannar as their Kinessi her name would be:
Elexia Marindur, Kinessi of House Serannar.

What orgs will I be in?
You will no longer been in your House org. You will instead join the org of the new House. If you switch Kinships because of this arrangement, you will also switch in to the new kinship as well.

What happenens to my base reputation?
If you switch Kinships on a Kinessi exchange, you will loose 60 reputation from your old Kinship and gain 60 reputation from your new Kinship.

Do I get to change Racial Abilities?
If you switch Kinships on a Kinessi exchange, you can never take the racial ritual of the kinship you are joining. You can, however, retain the one you received in your home Kinship.

What if there is war with another Kinship?
If war erupts between the Kinship you are Kinessi of and another that is not your home Kinship, you are expected to fight for the Kinship you are Kinessi of.

What if there is war with my home Kinship?
If war erupts with your home Kinship you are expected to return home and fight for your home Kin. Whether that happens or not is fully dependent on the character and circumstances. Socially it would be expected for you to return home.

Who handles a Kinessi's marriage negotiations?
The original Head of House is the person who will negotiate a marriage contract for the Kinessi. The new HoH, of course, is expected to advocate for their Kinessi, but the original HoH has the final word on the negotiation.