Why cant the Client Accept the job

OVERVIEW: 

Sometime the client or yourselves cannot accept the quote,There is two possible reasons for this.

1. The quote has expired: Actions to take: 

Resend the quote or Revise the quote then you or the client will be able to accept

2. The job has already been scheduled in the Calendar

This means that the status of the job has moved from "SENT" for example to Scheduled, so the implication is that the job is already approved or accepted.