Hi everyone - new to the whole FF game and this forum

I have about 25K worth of Amex Plat points which I would like to get over to my UA account (only has 15k in there) in order to redeem an upgrade on flight to LAX, but can't find the best way of doing it - any ideas

Thanks for your help
Mark

Amex Plat, HH Gold, SPG Gold, BMI Silver, UA, DL