I have a list called Contacts, with 4000+ entries. It currently has a dropdown choice column with four specified values for different offices (MAO, NHO, MEO and CTO). I want to convert this dropdown choice column to a lookup column that links to a newly created list with the four offices in it. The reason for this is because I want to use Mark Rackley's cascade dropdowns to filter Contacts by office.

From what I understand you can't directly convert a Choice field to a lookup field. So I thought I'd just create a new lookup field that links to the new list with the offices. The problem is there are already 4000+ items in this list that would need to have the applicable office chosen in this new lookup field.

Is there a way to create a workflow that will look at the value in the choice field and then select the matching value in the new lookup field for all the contacts? For example, it sees MAO in the choice field and then selects MAO under the new lookup field.

1 Answer 1


Yes, you can write sharepoint designer workflow to be executed on item change. In workflow, write step to "set value in current field" i.e. set lookup field with same value as choice. Now to trigger the workflow you will need update to each item so as workflow will execute,

  1. Create a temporary single line of text column - "TempDummy"
  2. Edit the list in quick edit mode
  3. Enter any value in "TempDummy" e.g. 1
  4. Drag the value of "TempDummy" in all the rows below.
  5. Once you save the changes, workflow will get executed and lookup column value will be updated as per choice field.
  6. Once all lookup values are updated, delete the "TempDummy" field and workflow

Do you need help in writing the worklow step ?

  • So the TempDummy field is used to trigger the workflow? Do I need to drag it down for all 4000+ contacts? Also, what parameters to start the workflow? Thanks
    – MoxMoxMox
    Commented May 13, 2016 at 2:15
  • Yes you need to drag for all 4000+ contacts or another option is if you can write powershell script to update dummy field to any value for all record (using for loop) that should also do the trick. To start the workflow you need to make workflow trigger on "when item is updated". Commented May 13, 2016 at 4:05

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