Macro next_layout 

macro_rules! next_layout {
    (@cmd ($cmd:expr) -t $target_window:expr, $($tail:tt)*) => { ... };
    (@cmd ($cmd:expr)) => { ... };
    () => { ... };
    (($cmd:expr), $($tail:tt)*) => { ... };
    ($($tail:tt)*) => { ... };
}

Move a window to the next layout and rearrange the panes to fit

Manual

tmux ^0.8:

next-layout [-t target-window]
(alias: nextl)