A system and method for producing liquefied natural gas (LNG) from a natural gas stream. Each of a plurality of LNG trains liquefies a portion of the natural gas stream to generate a warm LNG stream in a first operating mode, and a cold LNG stream in a second operating mode. A sub-cooling unit is configured to, in the first operating mode, sub-cool the warm LNG stream to thereby generate a combined cold LNG stream. The warm LNG stream has a higher temperature than a temperature of the cold LNG stream and the combined cold LNG stream. The combined cold LNG stream has, in the first operating mode, a higher flow rate than a flow rate of the cold LNG stream in the second operating mode.