Does the flash overwrite the AT+CWJAP_DEF call each time with the same ssid/password?

Question

Microcontrollers

The first time they called AT+CWJAP_DEF="USER","123" - saved to flash.
The second time we call the same thing, AT+CWJAP_DEF="USER","123" - is the flash overwritten? Or checks that there it already is?
You need to know not to kill the flush with multiple restarts.