Outer Mirror: Replacement

Remove the door mirror assembly. Refer to REMOVAL , Outer Mirror Assembly.
Warm the area around the mirror holder with a hair drier until the edges of the mirror holder become soft (about 2 or 3 minutes with a 1,000 W drier.)
Use a flat-bladed screwdriver without sharp edges to lift the mirror out of the mirror holder. (Also remove the connector from the back of mirrors with heaters.)

Fig 1: Using Flat-Bladed Screwdriver To Lift Mirror Out Of Mirror Holder
Courtesy of SUBARU OF AMERICA, INC.
Warm the area around the mirror holder with a hair drier until the edges of the mirror holder become soft (about 2 or 3 minutes with a 1,000 W drier.)
Remove the backing of the new two-sided tape, and push the mirror in to install it.
CAUTION: Unless the mirror holder is warmed sufficiently, the mirror holder edges may be damaged or the mirror cracked.