Yes. 

Go to the diary, single left click on the estimate/job you want to edit the timings of.

Click Feedback in the top right corner. You will see a section called Geolocation and times click edit next to this.

You can only edit the time the engineer 'clicked' accept, travel, arrive, leave. You cannot edit the location.

All times must be sequential, i.e. the leave time must occur after the arrive time.