Is there any way to access SSH if I forget my password?

If you simply say ssh, you don't know which os it is, and it's important whether the lost account is root, and the root account is usually off, so it can't be processed remotely.

If I were to say it's Linux, access using pem, or key, requires generating a key while logged in, so it's not available in the situation of questioners who can't log in.

If it's a normal account, you can access the root account and change the password

However, if you lost the password of the root account, the story will be different.

At this time, it cannot be processed remotely, and when booting directly in front of the equipment, the grub script must be modified to run bash immediately.

In other words, you will run the shell of root privileges as soon as you boot, so you can change the password immediately.

You can proceed by referring to the link below.

https://dang-dang12.tistory.com/20