She tried to 'smooth things out' [=end an argument or disagreement] with her daughter-in-law, but the damage was done.
They 'smoothed the way' for a quick end to the dispute. [=they made it easier to achieve a quick end to the dispute]
Her time at college wasn't all 'smooth sailing'. [=she had some problems/difficulties during her time at college]
(..) or otherwise unbecoming manner, you are to inform me immediately, so that I can deal with it immediately. It may not always run smooth, but we're trying to make it as painless as possible. Thank you, sir, but I expect a certain amount of pain. - Any questions? (..)1997 G.I. Jane