Capitulation is a Document in the Rise of the Tomb Raider: 20 Year Celebration DLC Blood Ties. It belongs to the Atlas de Mornay set and consists of a letter written by Lara's uncle Atlas de Mornay, finally admitting defeat and ceding the Manor to Lara.
The address on the letter is Lara Croft, 142 Abbingdon Road, Guildford, Surrey, England, AL9 5NQ. This address is of course fictional, there is no such road in Guildford. The zip code, though, is that of Hatfield House.
I have received a notarized affidavit confirming Amelia's grave and the discovery of the burial crypt within the Manor premises. While I can't fathom why your father would hide your mother's fate from her own family, I cannot deny that any legal claims I may have had on the estate are now null and void.
Croft Manor and the remainder of your father's assets are now yours in perpetuity, to do with as you wish.
If there comes a time when you require assistance in managing the estate, I hope you will consider contacting me to retain my services.Sincerely,