Leaving and re-entering on 30 day visa

Hello,

My girlfriend, Phoebe White, has a 30 day Vietnamese visa starting on the 25th February to 25th March.

Unfortunately she may need to return to the UK next week for a funeral. If we enter Vietnam on the 25th February, will she be able to go back to the UK and return to Vietnam a week later with her current visa or is that not allowed?

Many thanks,

Sam Ditton