Anyone EBF trying to transition to formula?

Hi ladies, I am due to go back to work on 1st Feb full time. That includes extensive international travel where I will be away from my baby for 3-5 days at a time. I am ebf now but will need to transition to formula because of that. I was planning to do this gradually in Jan so it's not that stressful for baby. Has anyone transitioned entirely? Any tips and advises?