veeva, Welcome to MRI. I am not sure of the answer to your question, but it came up earlier this summer as well - see Re: Does converting UA miles to Marriott Rewards count to Lifetime points?
Welcome to Marriott Rewards Insiders veeva! I'm so glad to have you as part of our community, and am glad to see you've already jumped in with a great question. As you'll quickly find, if you haven't already from jakeal's response, the other Insiders are very helpful and insightful, and are always willing to help you with any travel questions, tips, etc. that you have. You can also always reach out to myself, The specified item was not found., @katiec or NathalieF with any questions or comments you have. We make up the moderation team on this forum.
You ask a great question, and I am looking into finding an answer. I will reach back out to you once I learn more. Thanks for posting!