How to tell my sister I can’t make it?

I texted her to see if she was around so I could give her and her husband their wedding gift. She said she was working from home and busy at night so I could come during the day.

I was trying to get it to her because I’m moving in 3 weeks and she’s going on a honeymoon for roughly 2 weeks. I thought she was leaving Wednesday but she’s actually not leaving until Monday. I realized tomorrow doesn’t work for my fiancé so we’ll do it another time but I totally forgot to respond to her. I’m gonna text her tomorrow but don’t know what to say. Advice?