The Daily Nosh: Proverbs 25:15

Through patience a ruler may be persuaded, and a soft tongue can break a bone. (TLV) 

Nosh 

Two things are effective and necessary to consistently persuade or gain favor with a person in authority. First, a soft respectful tone in the voice and words of entreaty create an atmosphere of receptivity. Second, humble persistence while waiting for a response, has the best chance of getting a positive result. It is good to bear in mind that leaders do not usually respond well to frustrated insistent requests. Nor will they typically be bullied or rushed into doing our bidding. Solomon reminds us that the objective is to persuade not offend.