Need help the words I'm using are to difficult to understand by the person I'm sending to?

Thank you for your enquiry regarging the availability of office space to rent on the third floor. The current tenants will be vacating the building at the end of the month and they will be taking everything with them except for the partitions and the furniture in recepion which you can negotiate to keep if you wish. Please call me during office hours between 9am and 5pm Monday to Friday to discuss the rental options floor space required layout of partitions and the period of lease.

try this:

Thank you for your enquiry about the office space to rent on the third floor.
The current tenants will be leaving at the end of January and they will take with them all furniture and fittings except the partition walls and reception area furniture. If you are interested in using the partition walls or reception area furniture for your use please let me know so we can negotiate a deal about that.
There are many details to work out about the lease and I would appreciate it if you would please telephone me between 9am and 5pm on any weekday to discuss your needs.

So what is your question?

make it easier for him/her.

office space for lease
for inquiries pls call #
9:00 am - 5 pm

period

<>Thank you for asking about office space to rent on the third floor. The occupants will be leaving at the end of the month. The dividers and some furniture will be left there and we can talk about you using them. Please call me between 9am and 5pm Monday to Friday to discuss the details.

thank you for asking about the office for rent in third floor. people who are renting it now will leave at the end of this month. they will take everything and leave the partitions and furniture. you can ask to keep them if you want. please call me between 9am and 5pm monday to friday so we can talk about all details and how long you're going to lease the office for.
Anyone should understand this, I put it in very easy and basic English

Simplify and spell check

Thank you for your inquiry regarding the office space on the third floor. The current tenants will be vacating the building at the end of the month; they will be taking everything with them except for the partitions and the furniture in reception area which you can negotiate to keep.

Please call me during office hours - 9am to 5pm Monday through Friday to discuss the rental options such as floor space, layout of partitions and the period of lease.

Translation!!!
Thank you for asking if we have office for you to rent in third floor.
The people who renting that office right now will be moving out at the end of the January. They will take all their stuff with them except the furniture (sofa. side table, etc) and the thin walls that separates some areas in the room. If you are interested in these items and like to I can give you the number to contact the people and make a deal ;)
Please call me 9:00 am to 5:00pm, Monday to Friday.
We will talk, then i might invite you for coffee and we make a deal!!!!

How was it?

Reworded:
Thank you for your call. The office space you asked for will be available at the beginning of next month. The space will be empty except for the furniture and partitions in the reception area. Your use of these items is negotiable.

Our office hours of 9:00 AM to 5:00 PM, Monday through Friday. We will gladly show you this space and review your layout needs during that time.

I assume the reader doesn't speak English very well. Simplify some of the phrases and keep the sentences shorter. Something like:

Thank you for your interest in renting office space at your_location. We will have up to XXXX square feet of office space to rent on the third floor at the end of the month. The current tenants would like to sell the furniture and partitions if you are interested. Our office hours are 9am to 6pm Monday through Friday. Please call to discuss various rental options, space requirements, and lease terms.

It's not as formal sounding, but I think it's informative and simple.