Here's out it would work:
123 East Main Street- Fire Alarm
Assigned: Engine-1,2 Ladder-1
(Estimated time of 1st arrival: 1 minute)
205 East Main Street- Gas Leak
Normal assignment: Same as above.
But in this case: Engine-3,4 Ladder-2. (Estimated time of 1st arrival: 6 minutes)
In this case, consideration should be given to sending the second due engine on the fire alarm assignment to the Gas Leak and replacing them on the fire alarm with the last due engine on the gas leak. Note: when advising the IC that their second engine was "redirected" you may also ask if they want a replacement, sometimes they will not and the now extra engine can be cancelled (depending on your agency's SOPs)
This action reduces response time significantly, however it requires some thought and consideration before you undertake it:
1) Which incident is the higher priority? If the first is a fire, then it likely wont be smart to take units off that assignment for a lower priority incident. The reverse is also true, if the second call is a fire with people trapped and the first was a fire alarm or low priority call, it may be wise to redirect the entire assignment to the second incident and replace them on the fire alarm.
2) Where are the units coming from? Are they all training at Station-1, so the response time is actually not impacted? Or are they all coming from a distant academy or station so there is no point to making any changes?
3) How long has the first incident been out? If they have been there awhile, they may be able to put those units in service and all respond to the new incident. (Advising the IC that you have another incident in the area and asking about availability may be a very wise move). Likewise, have the units on the 2nd incident already arrived? If so, there is no point to cancel them!
4) What is the next run to go out? dispatchers for ems and fire should always be aware of the next run that is in queue behind the one they are dispatching. Sometimes dispatchers will assign a unit to a low priority call when a higher one comes right behind it that the unit they have just assigned should be reaponding to. This adds confusion, can impact response times, and is a sign of a potential lack of awareness. Take just a moment to look and see the big picture before you send out an incident. You may help save time, or a life.
Hope this opens some minds to the ways that effective, dynamic, empowered and proactive dispatching can reduce response times and help improve effectiveness!