If you don't have a griddle pan,

[WinkyWinkola]

what can you use instead?

I want to make chicken paillard and the recipe says griddle for 4 mins each side. Don't have a griddle. Any idea?

Dry fry in a frying pan?
If it is more for appearance (the lines) you can heat a skewer in a flame ad press this agaist the chicken to make charred lines.

Stick a cake rack, or the rack out of your grill tray from your cooker, over a frying pan, and slightly increase the heat. Also good for sticking a bit of extra flavour in anything, if you put stuff in the pan which now won't touch the meat