Don't worry, the milk production will drop a bit but will not to zero.
I was out of town for training for one month when my baby was around 1 year old. I just keep pumping in the morning and evening to keep the milk production. I also squeez out some of the milk in the toilet during day time if I found it congested.
When I come back after 1 month, my baby still can be breast feed face to face.