You can call a action in QTP by the following:

1. Insert > Call to Existing Action
2. Select the "Test From" (If "Action" is being called from 
another Test)
3. Select the "Action" you want to call
4. Then select the Location, where the "Action" needs to be 
called in the current script
5. Click "OK"

Or you direct write the script as below in the line where 
you want to call the action:

"RunAction <ActionName>, (Iteration)"

Here, "<ActionName>" is the Action you want to call and 
the "(Iteration)" is optional where you can define number 
of iterations you want to execute.

Eg:
1. RunAction Action2, OneIteration (For single Iteration)
2. RunAction Action3, AllIterations (For All Iterations)
3. RunAction Action4, 1-3 (For iterations from 1 to 3)


Note: To Call an "Action" multiple times or to Call 
an "Action" from Other Tests, make sure the "Action" is 
marked as a "Reusable Action".