One of the most useful Android Apps I've found is Caller ID Faker. You don't have to pay anything to use it and you get 2 free phone calls, up to 2 minutes long, each day. To use the program you put in the number you are calling, then a fake number that you want the recipients caller ID to display. You can change your voice to that of a man or a woman (or none). Click "send call" and wait a few seconds for the call to connect.
Your recipient's caller ID displays the fake number you put in. This is called spoofing. It's useful because many people will not answer the phone for a number they don't recognize. I always put in a number that is local to them (using the same area code and prefix) to maximize the chances they will answer. This gives the impression someone local is calling them and they may think a friend is calling to give them a new phone number or something of the sort.
Here's a screen shot of what this looks like on my phone.
If you need to, you can record the phone call.
Considering most of our calls to confirm presence are short and to the point, the free 2 minute mode is sufficient. If you need more for a more involved or serious case, you can purchase credits for longer phone calls.