How do I do this work when I spend time with a software company visiting customers?

Recently, we need to arrange for the case customers of two software companies to check the software application. It would be easier to separate the two arrangements. In order to be able to see them all at once, we asked the two case companies to be arranged in the same city, and the time was even closer.

In addition to our department, we also need a human department. In this case, it involves 6 teams, which is complex enough.

I first communicated with the two software companies about the location where they went, and reached an agreement that the biggest city was the city where tickets were not easy to buy. This made the schedule difficult, only the forward schedule is required, which requires the time of the case company to confirm. It's easy to talk about the time between the two companies. It's too late, so we need to advance. Then I confirmed the time of manpower, the time for human resources to go on a business trip, and the time for sending a salary next week. I finally decided to move forward for two days, and there was basically no big change, 2 days in advance is a solution with the next company.

According to the schedule, the destination needs to be confirmed first, and then the relevant tickets and air tickets need to be checked online. The other is to talk to several internal departments about how long they have been arranged and when they can be done. Then, they will talk to the software company about the feasible time period, and the software company will negotiate with the customer company, in this way, we can turn around to determine this matter.

I hope that no more complicated time schedule questions will be given next time.