ATP check in R/3 or APO (rules-based product substitution)
is it possible that a material substitution is also done in an outbound delivery (VL01 or VL02)?
Or is this only possible in a sales order (VA01 or VA02).
In the sales order you can check for alternatives via RBA, but for the actual delivery you have to accept and just copy over the items as created in the sales order. For those you can only execute a new ATP-check with the basic methods product availability, product allocation and forecast. But no advanced method as RBA or MLATP.
These are reserved for the sales order only!