When on duty as K-9 you still do everything like normal. You will respond to panics, do callouts in RTO, participate in pursuits when needed, perform traffic stops, help on foot pursuits, etc. Nothing is  different. However, there are a few things to note:

No more than 4 K-9 units on duty (More with permission from K-9 Supervisor+ (K-9 Officers active as a dog count as 1). There must also be at least 3 ordinary units on patrol before K-9 can activate. 

When active as K-9 you should avoid primary when not necessary, you can however take secondary and tertiary as usual.

K-9 Officers are not permitted to ride along with other K-9 officers unless this is authorized by a K-9 Lieutenant+ or the second officer is a dog. An introductory ride-along for new officers can be arranged with authorization from a K-9 Lieutenant+.

K-9 Units will NEVER transport a suspect, this is incredibly dangerous as the suspect is in close contact with the canine which is unsafe.

Shots fired (See 305) Shots fired / High-Risk Situation)