Best policy in a situation like that is to bring a solution to the broker and get it done. In emergency situations lines get blurred and it’s more about the end result as long as everyone is on the same page.
Hire a power only to cross dock it and bring your trailer back, then the broker can repower it from there. Or, hire a power only to grab your trailer and deliver it, then bring it back or find a place to have it parked until your fixed.
If you can’t do that yourself then see if the broker can arrange those things. Pretty much expect any revenue from that load to be gone. It’s all about not letting the customer down at that point.
I can’t say where or when, but I recall reading something about, having a Legal right as a Contract Carrier to arrange forwarding or final delivery, due to extenuating circumstances, essentially acting as a Broker. I did it once, on a load, after an accident. I hired another Carrier to finish the delivery. $600 load,I had already ran halfway, cost Me $800 to get it delivered, and I let the Carrier Load my trailer back, Then He dropped it at the Shop. I was happy to only lose $200 on the Load at that point. One less worry at the time .The original Broker was kept informed.I paid the $800, and later, collected original $600 from Broker.