It's wrong to interrupt others when they're busy.
Jenna and Marie are both on the phone talking to customers, and Jenna's customer just asked a question only Marie can answer.
Jenna wants to answer the customer's question.
Jenna asks the customer for a phone number where she can call him back.
Jenna interrupts Marie's phone conversation to ask the customer's question.
After Marie hangs up, Jenna asks the customer's question then calls him back to pass on the answer.
Marie answers curtly and Jenna relays that information to her customer.