A pre-approval - most likely no but possible - it would be an extreme situation for the applicant's financial condition to change drastically enough to cause you to withdraw a pre-approval. A pre-approval should only be issued after full verified underwriting criteria has been reviewed.
Approval subject to - this would be a conditional approval and failure to meet any of the conditions could be reason for denial.
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The opinions expressed are mine and they are not to be taken as legal advice.