To try and clarify what I am looking to do:

I open up a new record and it looks like this going down the form:

Registration No.
Field 2
Field 3
....
ReRun(Combo Box)
Comments

ADD CANCEL UPDATE FIND CLOSE <====Buttons

The Registration No. is the primary key for this record. The Rerun field looks up past Registration-No's and through a query displays a past Registration-No by prompting the user for it and also it displays the corresponding Comment for that Past Registration-No. It stores the past Registration-No. I have the Comment field of the current record as a Combo Box, but I believe it could be a field box from the table the form is based upon, or a Text Box, I'm not sure which one is the best to have for a proper solution.

What I'm looking for is when I'm in a New Record, I enter in the appropriate fields then when I come to the ReRun field, if I bypass this field I want to be able to enter an appropriate Comment field for this New Record.

But I would also like the option of; when I come to the ReRun field I would like to prompt for a previous Registration-No and store that number in the ReRun field and the corresponding Comment of that prompted Record return and be stored in the Comment field of the Current Record.