To create a new Yes/No field you first need to identify the 'DataMember' of the original True/False field.

You can identify the DataMember using the following steps:

1. Open a Report in Design View
2. Hover the mouse pointer over the current True/False field

3. In this example, the 'Available' field has a DataMember or 'IsAvailable'
4. Keep note of this for the next step.

The next step is to create a new Custom Calculated Field, to do this:

1. Right-click the Module Name within the Field List

2. Select 'Add Calculated Field'
3. The Calculated Field will now appear in the Field List
4. Right Click the Calculated Field and select 'Edit Expression'

5. Add the Expression in the format Iif ( [DataMember] , 'TrueValue' , 'FalseValue' )
6. e.g. Iif ( [IsAvailable] , 'Yes' , 'No' )

7. Click Ok to finish
8. Drag and drop the field to your report