Block field updates, but allow new values to be ADDED

[Anonymous]

Is there a way to block field updates so that existing data is not removed/overwritten, but should we want to add a NEW value to that field, it will be added to the field?

Example: for a Product Interest field, a lead already has Product Interest A written to it. When on a landing page, the lead then completes a form and in the Product Interest field, they select Product Interest B. I want to retain the existing value of Product Interest A, but also write Product Interest B to the form field in Marketo.

Do I do this via the Block Field Updates tool? 

[Helen_Abramova1]

Hi Andrew,

I would suggest using tokens for that and append, neither block nor rewrite the field.

Helen

[Josh_Hill13]

Right, you would NOT block the field for flow actions or form fill outs. The process would be to use a multi select OR a second field:

Product Interest
Product Interest Writable

If Product Interest Writable is Changed, then if Product Interest is Empty, Product Interest = {{lead.Product Interest Writable}}
Otherwise, Product Interest = {{lead.Product Interest}} {{lead.Product Interest Writable}}

Change Data Value, Product Interest Writable =NULL (to avoid issues on prefill of forms.)