A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hi Jenna,
There are several ways to customized your timelines in Excel. You can add more dates, move dates, change layouts and colors and apply different styles. Since you want to condense your 12-month planning timeline to 6-month planning timeline only, we suggest that you check out this support article. You can achieve your desired result by using PivotTable by following the steps on the link that we have provided.
If the steps provided in the link do not work for your timeline, send us a link of your sample data file so we can further assist you.
Update us on how it goes.