I'm sorry. We can celebrate your birthday when I return.
The daughter continued to cry and explained to her dad that she did care about him being there on her birthday.
The father apologized and asked if there was a way they could compromise in order for him to go on his trip and for her to celebrate her birthday.
The father and daughter worked out a plan to celebrate her birthday once he returned from his trip and apologized again for leaving on her birthday and upsetting her. The daughter accepted the apology and although the situation wasn't ideal, it was a compromise.