This is taken from an actual e-mail conversation with a somewhat troublesome
staffmember. As background I work for a graduate school in computing support.
It is a small school so everyone knows each other. 

<StaffMember>:Good morning - My computer continues to freeze quite a bit.
Early last week *bleep* said it should have its desktop rebuilt, but that it
will take a full day to accomplish this task.  It needs to be done on a
Saturday or a Sunday, or on a weeknight after 5pm, but it needs to be done
soon, before the computer dies.

<Me>:<StaffMember>, the Computing department works standard hours just like
the rest of *bleepschool*. We have no staff on Saturdays/Sundays or after 5pm
on weekdays.

<StaffMember>:Then obviously it will have to be done during the day if this is
going to solve the freezing problem.

<Me>:Of course, if you want to give us a good day the work can be done, I will
put it in the schedule. In general Fridays are bad as we are often swamped
with students.

<StaffMember>:No problemo.  Whatever is good for you.  Just let me know.

<Me>:OK, tomorrow it is. I will be by first thing in the morning to pick it
up.

<StaffMember>:Sorry <Me> - My computer cannot be taken away for a day when I
have a class going on.  Friday is a better day to do it.  If not, it will have
to be sometime next week that is not on a Wed/Thurs.

<Me>:OK, this is why I asked you to name a day, that is not Friday, when we
could do it. Please write back with a date when it is most convenient for you
and I will schedule your computer to have an overhaul.

<StaffMember>:Tuesday, the 27th of January is probably best next week.  If
not, then Monday, the 26th.

<Me>:I have your scheduled for Tuesday January 27.

Lesson of the day: When negotiating a schedule don't say whatever/whenever
unless you mean it because that means "at your convenience."