Alan, aged 48, was last seen in Oldham town centre on Greaves Street last Thursday (November 3).
Alan is described as a white male, wearing grey tracksuit bottoms, a black regatta jacket and black trainers.
Alan is also known to have links to the Longsight area of Manchester.
Officers are becoming increasingly concerned about Alan and want to make sure he is safe and well.
Anyone with information about Alan's whereabouts should contact police on 101, or 999 in an emergency.
