If you have not substantially changed your submitted schedule for the recovery (you added resources or simply started some tasks to share a workspace), your original baseline remains.

A baseline is never updated. It is the original submitted project schedule and is the contract plan. You saved a copy when it was accepted as your execution as-built and set it as its own baseline before actualizing any activities. Then you began updating the  as-built. The as-built uses that unactualized schedule as its comparison for progress.

The client is waits for you to send in your first monthly estimate schdule. When it arrives he will save it as the first month's progress and will assign the project plan as the baseline on his computer.

If you substanitally changed the schedule for the recovery, you submitted the partially completed project plan with a new path to completion to the client as a revised project plan. It is actualized to the point that the recovery schedule changes the project plan. When accepted the new path to completion is saved as your new as-built and it is set as its baseline before any updates are applied. Both you and the client change your baseline to the recovery plan that was accepted.

You have stopped using the old plan and as-built at revised plan acceptance. This requires some housework. You will have to go back and catch up activity progress from your old as-built to the new as-built to update the interim between submittal and acceptance.