depending on how your data is formatted you might be able to record a macro. the macro below transposes ten rows of the digits 123456 into six rows
123456
123456
...
becomes
1111111111
...
6666666666
you need some blank lines below your data - 4 more rows than the number of rows in your data, and say 4 blank rows above the data
123456
123456
123456
so an example with 3 rows, put the cursor on the first 1, start record a macro,
press ctrl B to start a rectangular selection (select-block)
press down arrow twice so that the three 1s are selected
press ctrl x to cut
press cursor down until you get below your data
press ctrl v to paste the column
press (right arrow delete) repeatedly until the column has become a row
press home to go to the start of the row
press shift down arrow to select the row
press ctrl x to cut the row
press cursor up repeatedly until you are on a blank line above your original data
press ctrl v
press down arrow until you're on the first row of your original data
if that looks useful then you can customise the macro to let the user enter the number of rows and columns and column width etc.
_command last_recorded_macro() name_info(','VSARG2_MACRO|VSARG2_MARK|VSARG2_REQUIRES_EDITORCTL)
{
_macro('R',1);
select_block();
cursor_down(9);
cut();
cursor_down(10);
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
c_enter();
cursor_up(10);
paste();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
cursor_right();
linewrap_delete_char();
end_line();
c_enter();
cursor_up();
deselect();
_select_char('','E');
cursor_down();
select_it("CHAR",'','E');
cut();
cursor_up(13);
paste();
cursor_right(2);
}