Working with multi-select picklists (MSP) is tricky. Here’s a hack to convert this picklist into a text field using flow so you can use it more easily.
Imagine there’s a MSP called “Zone” on the Account object. The values are “Zone A, Zone B, and Zone C”.
When this field is saved, the value is stored as “Zone A;Zone B;Zone C”. While this looks like text, it’s not. Let’s change that.
First, create a new text field called “Zone Value” on the Account object.
Then in an assignment step of a flow, perform the following two actions (in this order):
1. Set Account.Zone_Value__c = Account.Zone__c
This copies the MSP to the text field. Surprisingly, this direct copy works in flow.
2. Set Account.Zone_Value__c = SUBSTITUTE({!Account.Zone_Value__c}, “;”, “, “)
This replaces the “;” with a “, “.
Ta-da! Now you can use “Zone Value” like any other text field.
The takeaway
A multi-select picklist field can be converted into a text field in flow.