If your Marketo instance was migrated to the Adobe Admin Console (also referred to as “Identity Management System” or “IMS”), you have probably seen an option in Admin –> Field Management you haven’t see before:
That’s a surprise, as merging fields was an operation that only Marketo Support could execute. I don’t know why this option suddenly and without warning or documentation emerged and probably it’s a mistake. But either way: At the moment the function is available to you.
What does it do and how does it work?
Select a field from the right-hand side navigation and click “Merge Fields”. You can only continue if the field is not in use. (Same as hiding a field and changing the type of a field, all dependencies have to be removed first. Makes all the sense in the world, but it can still be utterly annoying.)
Now you can select the target field and declare which field’s value wins in case of conflict. Note that you can only merge two fields that have the same field type. Marketo will warn you if you try otherwise.
That’s it. After the process is finished your selected field will be gone and its value will be written onto your target field. Neat, isn’t it?
This operation might also serve as a backdoor to deleting a field, which is also a thing only Marketo Support can handle.
And what I have not tested so far is to merge a field that is synced natively to CRM.