To be able to accept (or reject) changes when using CtrlPrint you must first have your permissions set to do so at the project level. This needs to be done by the system or project administrator. The steps for doing so are outlined on the support page found here: Admin: How to give users the ability to accept changes
Once you have been given the ability to accept changes you will have access to the option in InCopy/InDesign.
Accepting all changes
The ability to accept all changes when using Windows is found under the "CtrlPrint" menu:
When using a Mac this option is found on the CtrlChanges palette (this is found under the "Window" menu in InCopy/InDesign):
Accepting one or more changes
You can accept and reject individual or multiple changes by using the buttons found on the bottom right corner of the CtrlChanges palette. Simply select the changes you want to accept or reject and then use the appropriate button.
Using the filter to accept changes between two dates or for a particular user
You can use the filter found on the CtrlChanges palette to display only changes made between, before or after a certain date as well as by specific user. This allows you to accept these changes while leaving all other changes in place.