Background: I met this person, S at a church I was attending at the time (I changed churches for different reasons). We became friends, because we had a few common interests, and I wanted to help S learn sign language (S wanted to become an interpreter, which is great. No problem with that.)
Situation: When we would try to get together, S would leave some vague comment or message to me, and I would be the one to mostly initiate the questions that were vital to scheduling a lunch time together. We have had a few lunches together, and they were enjoyable.
A recent situation that disappointed me is that S went away to a workshop, and we both expected to meet on Sunday for lunch, after her expected return on Saturday. S just now (Tuesday afternoon, 2 days later) messaged me that the workshop went longer than expected, and she wants to reschedule.
S did not communicate AT ALL that she would be missing the lunch date, either before or on the day. Not really appreciated. If S simply forgot and was busy, I understand that, but this is not the first time S has forgotten to communicate with me.
If I was in S's shoes, and I was missing a lunch date with someone, I would let that person know after I realized that I could not make it.
I have rescheduled many, many lunch dates (at least 6) with S in the past, and I am trying to figure out if this friendship is worth it.
I am asking how to communicate to S that if S makes a date with me, she either needs to stick with it or let me know that it won't work out in a reasonable time before the lunchtime. I do not mind if we reschedule it if needed, but I need to know at least a couple hours before, because when I make a plan, I stick with it.
EDIT I have expressed disappointment at missing another lunchtime with her, and have jokingly said something along the lines of "You better not miss the next one! Third time's the charm?!", and I am a pretty forgiving person in general.
Because of our busy schedules, we are not able to interact much. I work 9 to 5, and her schedule is varied.
She has expressed desire to have a lunch date with me multiple times.
Extra note: She is leaving to an out of state college by the end of August, and if this friendship is going to be salvaged, it would have to be within the next month or so.
Question: How do I communicate to S that her actions are not appreciated, without shutting down friendship?
Update
I responded to her, "Sure (we can meet up), when and where?" and she has neither seen the message or responded, and it's been more than 72 hours. I like to think that she has good reasons for not seeing or responding for a long time period, but at this point my expectations are low.
Second Update: I have scheduled a lunch date with her two weeks from this Sunday. We shall see what happens. I have very low expectations at this point.
Third Update S canceled that lunch, postponed it. Supposed to have dinner tonight, and she informed me that she can't make it due to a friend being induced to give birth today and that friend needs her. I understand, but this is going pretty far.