Programs: D.R.E.A.D. Gold Card holder; UA 1K/1.005MM; SPG Pt-195; PCC Elite; MR LT Au
Welcome to FT, firouzeh!
There is no way to merge miles from two different programs. Mileage Plus miles expire after 18 months of inactivity in your account. Any activity extends the expiration of all your miles for another 18 months.