EM5 -have to reset date and time every time the battery is removed to charge

With Olympus OM-D-EM-5  do we have access to this little battery and can we change the battery ourselves ? In big full frame cameras, these small batteries must be changed after 4 or 5 years and it is very easy to  reach the battery and change it. With Olympus is it true that the body must be returned to change this battery ?

Bernard