I am trying to see if automation is possible for the following scenario:

• when moving a Deal to a specific stage
• closing open Activity of a specific type (Task)
• To give a more detailed explanation...
  • I have a Estimates stage.
    • When an estimate is provided to the customer, I have automation setup to create a reminder task to follow up with the customer after a set period of time.
  • What I am trying to accomplish is if the customer calls back and schedules the work and I move the Deal to the Job Scheduled stage (next step in my funnel) can automation mark the outstanding Activity (Task) as done, so I don't have to manually do that.

I have tried everything under the sun but cannot find a way possible to accomplish this task. Is it possible with automation?