Component/s: Core Spec
P-Mode search is not defined and different systems may behave differently
As an example P-Modes may be identified in multiple ways. Eg.
1 Using the @pmode in the agreementref - although optional this imo is the most simple approach
2 combination of to/from/service/action - this would fail on mismatch and would return EBMS:0010.
3 combination of to/from/agreementref - ditto
4 Just agreementref
5 combination of from/MPC for pulls
6 just MPC for pulls