You can't. Only the admin/op/mod can unmute you. (unless you want to hack into the server console which is illegal)
Chat with our AI personalities
Type "/mute (player name)" in the chat to unmute.
try /pardon Greedy_Greifer
press F5
You have to be the host of the server.
No, though one of the key things about Minecraft is that you learn to teach yourself things... but if all else fails you can check the Minecraft Wiki.