First go to LENOVO:
https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-x-series-laptops/thinkpad-x1-carbon-type-20fb-20fc/parts/search
and enter your serial number or let the site detect your serial number.
To answer your question - No, only to i7-6600U Base: 2.6 GHz Turbo: 3.4 GHz
The RAM is all soldered to the mainboard.
There is a ''possibility'' of upgrading your storage, according to the specs.[br]
Some: M.2 SSD / SATA 6.0Gb/s (e.g. xxxG SSD) and Some: M.2 SSD / PCIe NVMe, PCIe 3.0 x 4, 32Gb/s (e.g. xxxG SSD PCIe NVMe
The Samsung SSD 970 PRO NVMe M.2 1TB works, according to Lenovo Forum.
https://forums.lenovo.com/t5/ThinkPad-X-Series-Laptops/X1-Carbon-4th-Gen-SSD-upgrade-to-1TB/td-p/4456484
You would probably be better off saving your money and upgrade to a new laptop.