1. “I’ve got someone calling soon, thank you for getting in touch and I’ll talk to you in a few days.”
This one disposes of the initial apology because you jump straight to the reasoning. You are busy and have other people wanting your attention but you are grateful for theirs. This makes the person feel wanted and appreciated that such a busy person will give them their time. The final rearranging of the call offers reassurance you are not just avoiding them although the vaguery of the time scale makes it significantly easier to call on your own terms. This one obviously doesn’t work when you are talking face to face as you then have to fake a phonecall and acting out a lie is never a good idea. Unless of course you have actually got a call coming.