If you need to postpone or cancel plans with someone then you can take a rain check. We use this expression when we want to politely decline an invitation or reschedule a plan, but also imply that we would be interested in accepting another one in the future. When you take a rain check on something it lets the other person know that although you are unable to accept their offer or participate in an activity now, you are hopeful that it will work out next time. It shows a willingness to reschedule for a later date.
If you have a project or task to do, and you have a very limited amount of time to finish it, then you can say that you're in a race against time.
When someone is on the ball, they pay close attention to the details of an activity or project. As a result, they are usually knowledgeable and quick to respond to changes.
Employers like to have employees who are on the ball because it means that they are competent and alert. This expression can be used in professional settings to make reference to someone’s work ethic. It can also be used in casual settings to say that someone is smart or organized in general. For example:
Have you ever worked on a project that completely changed the way your business operates? If that project was the outstanding achievement that your company needed to grow, it was a game-changer.
We call a person a game-changer if they can drastically affect the outcome of a situation. If you hire a new employee and they introduce visionary ideas and innovative strategies, they could be a game-changer.