BQ24610: About Safety timer reset

Dear experts, if timeout fault occurs(Safety timer), POR can clears the fault(Clear timer). What's POR? I must remove the battery or just only  remove the external DC adapter? Because the battery is hardly to remove(Battery is assembled in my equipment, it is difficult to remove from the charging system.), it's more easier to remove the external DC Adapter. If I just remove the external DC adapter(Battery is still assembled on my system.), safety timer can be reset? Thanks.