Salesforce Convert a Text to a Formula Field

I want to change a Text Field to a picklist. I know how to actually change the field type however I have several Formula fields that reference the Text Field so when I try and change the field type, it states that I cannot because they are referenced in a Formula.

You cannot deactivate Formula Fields, I cannot change the Formula field to TEXT(Field__c) until the field is a picklist. How can this be handles is the only way to change the formula to a place holder reference then change the field type to a picklist and change the formula fields to reflect TEXT(Field__c)?