First, and mainly for others reading this thread, let me make it clear that job related expenses, including a home office are not deductible for a W-2 job. I am assuming you are self-employed.
Let's say for example, the original home office was 5% of the floor space in your home, and you opened the new home office on Apr 1 2020 consisting of an additional 5% of the floor space.
What you will do is close the old home office on Mar 31st.
Then you will open a completely new home office on Apr 1, where the total square footage is 10% of the total floor space. Just make sure the close date of the old home office does "NOT" overlap the open date of the new home office. Then the program will "do the math" for you based on percentage and close date of the old office, and percentage and open date of the new home office.
So your 2020 tax return will have two home offices listed on it, for the same business.
