I'm sorry, I originally wanted to see the house with you today, but my colleague was sick this morning and asked me to cover for her. I am quite sorry about this. You can contact me whenever you are free and I will accompany you next time, ok?
口语一点不代表可以语法错误吧……
I'm so sorry, I was planned to go and check the house with you today, but my work-mate is sick, she wanted me to take her place for now. I'm very sorry, Will you please contect me next time if you were free?
I'm sorry that I planed to go with you to see the house today.However my colleague was ill this morning and askes me to work instead.Could you pls contact with us next time if you're free?OK?
"Sorry, I planed to today accompany you to see the house, but the morning my colleague ill wants me to help her shift! Sorry! Next time you free again contact me, good?"