Gather a small flathead screwdriver and the correct replacement coin-cell battery
Locate the seam or release point on the key remote
Insert the flathead screwdriver into the seam or slot
Gently twist to open the key remote casing
Separate the key blade section if needed
Remove the old battery
Note the battery type and polarity
Insert the new battery in the same orientation
Press the remote halves back together until they snap shut
Test the buttons to confirm the remote works
Reassemble any key blade or cover pieces if removed