Two elements cannot be saved to the same database field.

You cannot save two elements (data collection fields) in your program to the same database field - one will overwrite the other.  This may be needed where a program navigates to another prompt based on a menu selection, and where only one of two similar elements needs to be saved for the particular collected record.

On the prompt which occurs SECOND in your program and for the element you need to save:

Set the database field drop-down to <ignore>.
Add a button to that prompt.
Add the script below to the button's OnClick event, which sets this prompt's element to the elements of the first prompt:
$Prompt1.elementname$ = $Prompt2.elementname$

For visual assistance, please see PDF in the link.