Could you call someone over?
你能喊某人过来
Could you tell someone to come over?
你能叫某人过来吗
Holler him over,will ya?（俚 - 不礼貌）
刚看到你的另一个提问：
既不是请求,也不是喊叫,只是招呼某人过来.
招呼某人过来
Invite someone to come over （邀他过来）
Ask someone to come over （请他过来）
Tell him to come over （叫他过来）