If your master device (which you did not specify) has multiple I2C bus controllers, hook each device to a different bus. There is no way to change the RTC chip I2C address. The current I2C address of the device should show on the screen.If you are using an Arduino Uno, use the 5V pin Please find a snapshot of the data transfer which was shared by you in this thread before below: Here, slave address is 7 bit field.
For example, that a look at the following OLED display.
Figure 6: Successful I2C Write Byte Transmission. Whether or not it is configurable depends on the pin-count of the package and the number of pins that are needed to control the device.
Install them into your EV3 programming environment using the instructions found here. This address is not 0x78 or 0x7A as printed on the back of the OLED board.