macro for instrument changes

[Stefan Thomas]

Dear Lilypond-users,
I am sure there is an easy way to create a macro for the layout of
the two markup-commands in the below quoted example:

\relative c' {
c1^\markup {\bold \box "Englischhorn" }
c1^\markup {\bold \box "Heckelphon" } }

I would like to write something like
{ c1\change "Englischhorn" c1 \change "Heckelphon" }
How can I do it?
Thanks for Your support.
Stefan