Converting mega from ISP programming to UART

Hi Guys

Firstly apologies for incorrect terminolgy but i am new new to this

I have bought two Arduino Mega 2560 core boards from Ebay One came with a USB to UART bridge cable the other did not.

Now it looks like the one that didn't, i have to program using the ISP pins. This is new territory for me.

Is there a way i can reprogram the Mega that has been pre set for ISP programming to accept sketches via my USB to UART bridge cable ?

The board in question is below.

Thank you.

I'm confused.

Are both boards like the one you bought from Amazon?

The datasheet --- you did read it? --- for the board sold on Amazon says that the board can be programmed via either USB-serial or ISP.