We play regular on private parties and sometimes we get these requests upfront, f.i. the wife wants to sing a special song for the husband or vice/versa...

We do allow this IF She or He is willing to come to our studio for rehearsel!
This way we can transpose the song if needed(I can tell you that is mostly the case ) and also we find out IF she or he can sing.
If NOT we record the session and let them listen
Works great.

Fred