Creating a measure with if statement with text

The table visual I have created has columns for account IDs, prior region, prior territory, new region, new territory, and last year's sales associated with each account. These columns are from two different data tables (Prior & New). We re-allocated accounts to different regions and territories and want to show regional managers which accounts they lost, which they gained, and the associated sales with each of those accounts.

I'd like to create a measure using an IF statement to show =IF(PriorTerritory=NewTerritory," ",NewTerritory). I would insert a slicer so that regional managers could select their regions and see which territories are different than prior. Unfortunately, the IF statement is not working with the text fields.

Open to different ideas to make this work.

Thanks!