The Agency also asked for limited nationwide suspension of action to allow staff in other regions to provide support to those areas.
Prospect is still in dispute with the Agency over the imposition of the 2018-19 pay offer.
Members had agreed to work to the terms of their contracts, withdraw from incident response from Friday evenings to Saturday mornings and not take on additional shifts.
However Prospect had agreed that it would suspend the action in local areas if there was a significant incident which could lead to danger to life and limb.
Prospect negotiator Kevin Warden said: “Prospect is content for members from other areas who wish to support their colleagues in Yorkshire, Lincolnshire, the East and West Midlands, and Northants areas, on a mutual aid basis, to do so.”