Have a little light on the table with a button you can push to summon the server. This is similar to how in Brazilian churrascarias you have a red/green coaste

Have a little light on the table with a button you can push to summon the server. This is similar to how in Brazilian churrascarias you have a red/green coaster that you flip green if you want the server to come around with more meat, and red, when you're done.