Keep me posted.
C1Please update me regularly.
Count me in!
C1I'd like to participate.
I'm afraid I'm tied up then.
C1I'm busy at that time.
Let's firm up the details.
C1Let's finalize the specifics.
Save the date!
C1Remember to keep this date free.
Are you free on…?
C1Do you have time on…?
That works for me.
C1That time/plan is suitable for me.
I'm booked that day.
C1I have prior commitments.
Let's touch base next week.
C1Let's discuss this again next week.
I'm swamped at the moment.
C1I'm very busy right now.
Shall we make a date?
C1Shall we schedule a meeting/appointment?
I'm fully booked.
C1I have no free time.
Let's lock in a time.
C1Let's confirm a specific time.
It's all tentative at this stage.
C1The plans are not yet confirmed.
I'll check my diary.
C1I will check my schedule.
We'll need to coordinate our schedules.
C1We need to find a time that works for everyone.
Let's put it in the calendar.
C1Let's add it to our schedule.
I'll get back to you on that.
C1I'll respond to you after checking something.
Let's pencil this in.
C2Let's tentatively schedule this; it's not yet confirmed.
I'm tentatively accepting.
C2I'm inclined to accept, but I need to confirm.
Count me in!
C2I'll definitely participate.
I'm afraid I'm otherwise engaged.
C2I'm busy with other commitments.
Save the date!
C2Remember to keep this date free.
Let's keep it on the back burner.
C2Let's postpone this for now.