From the Groundspeak Knowledge books:
Adopting or Transferring a Geocache
Here are the steps to transfer the ownership of your geocache:
Log in to your Geocaching account and visit the adoption page
Enter the GC code (GCXXX) and click "Lookup"
Enter the username of the new owner and click "Go"
Click on "Send Adoption Request"
The potential new cache owner will receive an email. They need to log in, visit the adoption page and accept the adoption request
- The listing will transfer to the new account, the owner name on the listing will not change, but the link will go to the new owner
If the original geocache owner is inactive on our site and/or will not use the Geocaching Adoption Service, the interested new party must ask the original geocache owner to give Groundspeak written permission. The owner should inform us at http://www.geocaching.com/help from their Geocaching email account that this geocache can be adopted to the new party with their permission. If the geocache owner is unresponsive and the geocache needs attention, you may write a Needs Maintenance log or a Needs Archived log to the cache page, as appropriate.
Groundspeak will not process a geocache transfer without written permission from the geocache owner. Individual geocaches are owned by the person(s) who physically placed the geocache and/or submitted the geocache listing to geocaching.com. Decisions about geocaches belonging to someone who is deceased need to be made by the geocache owner's family since that geocache is now part of the estate.
Grandfathered geocache types cannot be transferred to a new owner. Neither the adoption tool on the website nor Groundspeak will be able to make the transfer for Virtual, Webcam or Locationless geocaches. Archived geocaches cannot be transferred, and rarely will archived geocaches be unarchived for the purpose of adoption.