I already know that you can relocate vehicles permanently to other firehouses, let's say you accidentally built an engine at a firehouse that it isn't supposed to be at. No biggie, you can just move it to the firehouse you want.
Also, for large storms and such, staging areas exist so for 24 hours you can temporarily send units and dispatch them out of there.
One thing that happens frequently in my area, is if there is a large scale fire, or units are OOS for the day doing training at the academy or OOS for mechanical reasons, other units from the surrounding stations are moved (relocated) to that firehouse for maybe around a few hours or so. Sometimes, I find myself dealing with major calls where half of my county can be on the call, and that leaves half of my county without adequate coverage. Instead of having 15 minute response times, if there was a feature where I could move a unit to a firehouse where it's units were out on a call, and it could temporarily be AIQ there until the other unit clears, that would be awesome.
Once the unit who's on the call is clear and available, the system could automatically make the unit that was covering the firehouse automatically clear and reroute itself back to its home firehouse.
This seems like a nice option because some calls drain my resources and it is a nice way to even out response times.
If you have any questions feel free to ask I don't think I am very good at explaining my idea.