https://www.marriott.com/loyalty/terms/default.mi#additionaltermsSection 2.8 says:
2.8 Transferring Points from One Account to Another
2.8.a. In accordance with the conditions for transferring Points as described in Section 1.6.c. Members can transfer up to a maximum of 100,000 Points per calendar year between any two accounts in good standing that have each been open for at least sixty (60) days, whether sending or receiving Points.
2.8.b. A new Member may receive a Points Transfer thirty (30) days after enrollment if the Account reflects activity including a Qualifying Stay or other qualifying activity as described in Section 1.6.d. After ninety (90) days from enrollment, a new Member is eligible to receive a Points Transfer regardless of their account activity.
2.8.c. Authorization to transfer Points must be initiated by the Account holder with the Points to be transferred by contacting Member Support. The Account holder requesting the transfer must provide the Membership Number of the Points recipient at the time of the Point transfer request.
2.8.d. Once the authorization for transfer is received and processed, the transferor relinquishes all rights to the transferred Points, and they become the recipient’s Points.
2.8.e. Miles and Elite Night Credit cannot be transferred between Membership Accounts.
