Change a yes/no field automatically with Key management

[Ramon19]

What do you exactly mean with pass both number? Ive looked a bit at how the update querys work and I think I can make it work. I only don't really know what i should fill in at the criteria. I think that what your saying is to make a criteria refer to the transaction numbers. So that the keys with a transaction number equal to the one of the master form wil change to yes. (and back to no when the keys return). However, I don't really know how this criteria should be build. Or do I get it wrong?

[RuralGuy]

They are different transaction numbers aren't they?

[Ramon19]

Well, each record of the master has a different transaction number because its a autonumber field and the primaire key. But each record of the master is connected with a detail/sub form. In the tabel of this form, there is no primaire key. This way the detail/sub form can hold many keys with the same transaction number as the record from the master form. That way the Master is connected with the subform