Wrong syntax?

Hi

I have a problem with my appl. I am trying to make a relation between to fields.
In this case it is between two tables (field name) =machine and (field name) = Machine_responsible.

When our users choose a machine type from the drop down, the field "Machine responsible" should automatically be filled out with the name of the responsible person.

I have tried to set up the below script - but it seems as something is wrong.

dat = MachDetail [Machine == input.Machine];
input.Machine responsible = dat.Ref_to_Machine;

Please see attached wp doc for further info. of my appl.

BR Skouboe