keyboard ribbon retainer base

I recommend taking a picture and posting it here so that we have a better idea on what is broken or detached from the keyboard connector.

Use this guide to learn how to add an image to an existing question:

iFixitでの質問に画像を追加する方法

If it's the connector that holds the pins that is damaged on the logic board the whole connector may need to be replaced by an experienced micro-soldering technician that does laptop repairs.

It may or may not be worth it depending on your circumstances and the value of the laptop.

If it's just the retainer flap, these can be re-attached most of the time and if it is like slightly damaged a little scotch tape may be enough to hold it in place and push the pins down so that makes contact and firm connection with the ribbon cable coming from the keyboard.