I need to know if there is a way to make a calculation field modifiable. Here is my calculation:

Case (

Project Initiation Form::Client="Wal-Mart Stores, Inc." , GetField("WM Project Tracking::Proto Size") ,

Project Initiation Form::Client="LOWE'S" , GetField( "Lowes::Proto Size") ,

Project Initiation Form::Client = "Kohl's", GetField("Kohl's Project Tracking::Proj type"), "not found")

In instances where the result is "not found", I need to be able to manually edit the field to show the correct information.

Make it a normal field with an Autoenter calculation instead of a calculated field.

Thanks. Worked wonderfully!

What can I do if the scenario is the same but for another field I need the result to be a date?

Just make the field a date field, and use whatever date functions you need... it will work the same as any other type of field.