Upload the DB from the plc to the programmer (I copy from the online view into the offline view). The actual values from the online copy will be copied to the actual values column in the offline copy. Make your changes in the offline actual values column, save and then download.
The initial values column causes much confusion - here's my explanation.
When you create a new variable declaration in a DB, you enter the variable name, data type and the required initial value (or accept the default initial values which is zero). When you save the DB, the initial value is copied to the actual value column - importantly this is only done the first time you create the variable. You are now free to edit the actual value column and save the DB - the initial value column will stay unchanged and will not affect the actual value column until you use the editor option called Initialize Data block. Using this option will copy all initial values to actual values.
The actual values column is what is transferred to and used by the plc.