As GP said, usually if the covenant isn’t being met but the company is profitable or has a good excuse the lender will not call the debt. They’ll work with you. I’ve seen tons of flexibility here from lenders. Usually the lender will start having more questions about the strategy and current forecasts if the metrics are underperforming and you’ll (CEO/CFO) will have to start being a bit more transparent than required or maybe just more frequent check in meetings to discuss status. In most cases, if you actually have a good story and have a healthy partnership the lender doesn’t want to call the loan and wants to see how they can help (within tolerance) get you back on track.
The moment the lender calls the loan typically, in startup land, there’s no cash reserves to pay off the debt and so the company is instantly insolvent and operations cease. This is why the lender is flexible, calling is typically a nuke for the business. But also, it can be a bit of a stop/loss. Meaning the cash in the bank can at least be recouped.