Hi,
Please try the following steps.
Step1: Create a Partition PT-PLAR
Step 2: Create a Calling Search CSS-PLAR and add PT-PLAR to this CSS.
Step 3: Create a Translation Pattern with the "Translation Pattern field" blank, this is very important. Then in the "Called Party Transform Mask field" enter the number of the Operator. Assign the PT-PLAR to this translation pattern and also apply a CSS that is able to reach the phone which needs to be called.
Step 4: Assign the CSS created in step 2 to the phone that will make the call. Reset the phone to apply changes. ( It is important that the Line does not contain another CSS since the line has priority over the phone.)
HTH
Manish