Can I change tyre 215 to 205?

Physically they should fit on the rim and tire without issue. The difference is going to be the rolling distance is a bit shorter for the new (to you) tires. 215 to 205 is 1cm difference in width. At 60% sidewall ratio, the difference of sidewall height would be about 6mm less, and the height of the tire would be 1.2cm shorter overall. According to this calculator, here's what the differences would be:

• Sidewall Height: -.24" (-.61cm)
• Section Width: -.39" (-.99cm)
• Tire Height: -.48" (-1.22cm)
• Tire Circum: -1.5" (-3.81cm)
• Rev./Mile: 14.33 (24.5 rev/km)

It also states, if your speedometer reads 65 mph (104.6 kph), you are going about 63.8 mph (102.7 kph).

These are fairly good estimates. If you can live with the difference, then yes, the tires will fit and work.

One other thing to consider is, if you have an all wheel drive car, you need to ensure all four corners are the same. Most vehicles which are AWD/4WD require this to ensure you don't tear up the transfer case.