Adding a shortcut to a macro ?

[Mosalie Rignon]

Hi,
when I create a new macro I have the option of adding a toolbar button
and/or a keyboard shortcut.

If I decide not to add one/both of these I can still access the macro
through th emenus.

Now, supposing I regret not havinhg added a toolbar button and/or a keyboard
shortcut....
How do I go back and add these options.
It seems to me that I have to get it right the first time round and no
looking back.

Surely there's some way to add a button or a shortcut to an existing macro ?

TIA

Mosalie