Oracle Solution for Error ora-39702

Solution for Oracle Error ORA-39702

ORA-39702: database not open for UPGRADE or DOWNGRADE

What triggered the Error:

An upgrade, downgrade, reload, or patch script was invoked when the database was not open for UPGRADE or DOWNGRADE.

What should we do to fix it:

Use STARTUP UPGRADE to open the database for upgrade or to apply a patch set. Use STARTUP DOWNGRADE for running a downgrade script or the reload script.