"Latching" a filed
I have a table with two fields FIELD A and FIELD B that represent a survey of people. I import a value into FIELD B (a simple yes, no, or undecided) from a previous survey and that value is displayed. At some point in the future, another survey is taken and the value is placed into FIELD A by the person taking the survey. I would like the value placed in FIELD A to also replace the value in FIELD B and then when FIELD A is cleared (in preparation for a new survey) FIELD B would retain the value until a new value is put in FIELD A (not blank).
Any ideas on how to do this?