EWM on 3PL and Migration WM to EWM

Hi Gurus,

One of my customer is using multiple 3 PLs systems, and planning to bring all different 3PL systems on single SAP EWM system.

And, for already existing WM systems , wants to migrate from WM to EWM.

We want to know the challenges we face, your experiences, learnings and any issues to be taken care initial stage.

Please suggest me on the same.

Thanks...

Srini