You can use “Replace” to perform bulk replace operations for string fields. This can save you lot of typing!

In this example, I change the path for a set of orthophotos in an image catalog, from the C: drive to the D: drive.

To perform this operation;

1. Open Field calculator by right clicking on the field where you want to change values
2. use the following syntax in the Field Calculator dialog   

       replace ( [YOUR_FIELD_NAME] , “Old Value”, “New Value”)

          3. Click OK

The syntax for the example below would look like this:

    replace([IMAGE],”C:”,”D:”)

 For more information on this topic, as well as other useful Field Calculator functions, see the following technical article from ESRI: HowTo: Use VBA functions in the field calculator