Help please this is crucial ...

i got two faces, one that's pointing left and the other pointing right. respective members names "left" , "right".

I got the member "left" on sprite 4. wrote the lingo to move him using keypressed (123).
What i need to do, is when on keypressed (124), member "right" replaces "left" and then to set loch for moving him with the respective arrow key.

Please if possible help me out, write me script down, Then explain to me why we did this for further projects.

Thank you