A lot of first-line managers treat their own manager as someone to keep happy.
So the report upward gets polished. The good accounts go first. The slow ones get a line at the end, or wait until next month in the hope that they recover.
In my experience, that is how you lose the one person who could have helped.
Managing up, the way I try to do it, comes down to three habits.
Honest numbers. "Sell-in is on plan, but sell-out to two hospitals has slowed." Sell-in, sell-out and distributor inventory are three different numbers. Reporting the one that looks best is not reporting.
Early news. "I want to flag this now, not at month end." An early problem still has options. A late one only has explanations.
A plan with the problem. "Here are two options. I recommend the first, and this is why." Your manager decides faster, and learns to trust your thinking.
And one line I never cross: loading distributor stock to make a month look better. It fixes one report and damages the next three, and the trust with it.
“Bad news early is information. Bad news late is a surprise.”

Lesson 2 of 6 in Step 8: Managing up and growing, with the full guide and a checklist for this week.