I was doing telephone coaching last week with a large manufacturing company. The prospect asked a technical question and the sales person put him on hold and came back a minute later with the answer. About 3 mins later he asked another question and again, had to out him on hold. I call this the ‘yo yo effect’. The strategy I taught him was ‘let me go away and get the answer for that; before I go, is there anything you would like to know?’
Once they request something else say ‘I know that, let me go away and get the answer to both things’. So even if you don’t know the answer to both, you no longer look stupid or frustrate the prospect.