Here are a few things to know about adding and removing picklist values in Salesforce.
If an additional value is added in Salesforce to a picklist field type, you will receive a notification identifying which forms this will affect.
Go to the form editor and add the additional value to your list of suggestions.
When a picklist value is removed from a field in Salesforce, you will have to manually remove this value from all the forms hosting this field.
If a lead field and a contact field in Salesforce have different values, the values in common will be available for use in Marketo.
If a lead field and a contact field in Salesforce have different values:
If a picklist of an SFDC lead has different values than a picklist for an SFDC contact, the common values will be used as default value options in the form.
If you remove a value from a picklist, you will have to manually remove it as an option from your forms.