Converting columns to lines

This is my first post and I hope this is an easy one to answer (or to understand).

I have a file where I have file lines of text on the same column. I need to convert the column into one single line.

Example:

A
1 x
2 y
3 z
4 a
5 b

I need this information to show like this:

A B C D E
1 x y z a b

Does it make sense?

Thank you.

Have you tried COPY-- PASTE SPECIAL-- TRANSPOSE?