During initial deployment of Signite signatures to your users, the original, non-Signite signature is saved, so you can always return to it for any reason.

1. Delete the Signature From Signite

To remove the deployed Signite signature from a user (or users), go to the Users screen, check the users you wish to reset, and click the Reset Selected button at the bottom of the list.

Note that the Signite app must be installed and activate on your Google Workspace account for Signite to be able to reset the signatures and re-embed the original pre-Signite signatures.
After resetting the signatures you’ll be able to remove the Signite app.

2. Delete the Signature From Gmail

To remove the signature directly from Gmail, go to your user’s Gmail Settings (the Cog icon at the top right corner of your Gmail screen) -> See all settings, and scroll down to the Signature section.
Delete the signature you’ve deployed from Signite to finish the process.
You can also choose a different signature from the list if there is one, or create a new one from here.

Note that on the Free plan (and on Premium if it’s set up that way), your Signite signature could overwrite the Gmail one after a while.
If you’ve chosen to leave Signite, avoid this overwrite by removing the Signite app from your Google Workspace account.