Issue with updating fields

[Anonymous]

Hi everyone, 
I'd love to get some help here.

When we upload lists of leads / contacts, it's automatically update the existing contacts details, such as phone numbers, emails etc.
Unfortunately not all of the info we have in our lists are the most updated what so ever.

I've got a request from sales to avoid updating fields of phone / emails for leads / contacts that are owned by sales, 
Do you have an idea how to do that?

Thanks!

[Anonymous]

Ronen,

This is easily fixed using Field Blocking:

Admin > Field Management
Select the field you want to NOT update, then use the menu to select Block Field Updates.
Choose the methods of updating to BLOCK.

So now if a record already has a value, Marketo wont' update it on List Import. Empty values will still be updated.

[Anonymous]

Hi Josh,
Thank you for your comment.
This is something we thought about earlier, but what if user filled a web form and updated his phone number?  
If I'll use your offer the field won't be updated...

Any ideas about that?