It depends the length of your job offer at the time the LMO was issued. Check your LMO to confirm the length of your employment e.g. if your job was a 2 year contract(or more), you still have at least one more year left on the LMO. In that case, you can apply for another closed work permit(after renewing your passport) and ask for the remaining year(s). Make sure you include a copy of the LMO again.
If your job was a 1 year contract, you`ve already used that year. In that case, you would need a new LMO even if you work for the same employer in order to renew your work permit.