going back to old tenant prospects / waiting lists

[Colleen F.]

In your business model, how do you go back to old prospects for your rentals and when?  In June I advertised a property when tenants said they were leaving.  After I had showings lined up the current tenants stayed and I had to cancel showings. They are now leaving although getting a date is challenging. Some of those previous prospects said keep in touch if it changes. One  had seen the house a year before and said he wanted to apply before Even seeing again.  It is a small community for full time rentals (lots of student rentals then summer rentals) and this house  is affordable for the size.  Some prospects may still be looking but it is 6 months. Do you normally call/ email old prospects ,send them the ad, or just assume they will see it if they are still looking.  Just curious, if I had already seen as acceptable application or it was a month ago I would definitely go back but this is more like an unofficial  waiting list. I don't want to convey favoritism or desperation but I also want to decrease vacancy. 

What do you normally do?

What would you do in my situation?