If need be
Definition 1 of 1
Pro Tip 1/3Emergency Plan
Use it when you're talking about a backup plan or a last resort option, not your first choice. 
We can cancel the outdoor event if need be, but let's hope for good weather.
Pro Tip 2/3Slight Uncertainty
Implies that there's a small chance you will have to take additional action, but it's not certain. 
I think we have enough chairs for everyone, but I'll fetch more if need be.
Pro Tip 3/3Flexibility Highlight
This phrase illustrates your willingness to adjust or accommodate changing situations. 
The agenda is flexible, and we can skip some parts if need be.