Update yMKT Interaction status from SAP CRM!

Hello, Friends!

I'm absolutely new in SAP yMKT and need some help.
I have interaction in yMKT with the current IA_STATUS = 'PROMO_OUTBOUND'.

This status was assigned to this field when I sent the promo to SAP CRM!
Now I want to update this IA_STATUS to 'PROMO_ASSIGNE' from SAP CRM!

But I don't know how to do this because I don't have enough experience in SAP yMKT.
Can anybody help me with some advice or some 'step-by-step' guide?
Thanks!