LTE: Is it possible MME gets changed but SGW does not change during the handover ?

Question

Is it possible that MCC MNC gets changed in the same Diameter session without changing session ID while in Roaming???
As I have come to across an unsupported scenario when some users are roaming in Iceland operator MCC MNC and suddenly switch to different operator MCC MNC which belongs to the USA within the same DCCA session i.e without closing the PDP context and opening a new one (that should not be possible, unsupported scenario). Is it possible??? I'm confused here.

Answer 1

I have not found any message exchange between target MME and source SGW in handover signalling, so it means there is no possibility when MME gets changed and SGW does not change during the handover procedure.
One more logical answer I would like to share since MME selects the SGW during the attach based on the current position of UE. Similarly when MME gets changed as part of handover procedure, decision to carry on with current SGW or choosing the different SGW should be with MME only.

Answer 2

In 29.274 specification, one message name as "Modify Access Bearer Request" defined. This is an optional message so it might not be present in S11 interface. MME executes this procedure towards the SGW when all the S1-U bearers at the eNodeB gets changed for an UE. In message definition mentioned that if MME gets changed as part of TAU/Handover and SGW does not relocate then new MME sends this message to SGW to update the tunnel end points of eNodeB side.