oracle error - ORA-00277: illegal option to the UNTIL recovery flag string

ORA-00277:	illegal option to the UNTIL recovery flag string
Cause:	Only CANCEL, CHANGE and TIME can be used with the UNTIL keyword.
Action:	Correct the syntax.

oracle error - ORA-00276: CHANGE keyword specified but no change number given

ORA-00276:	CHANGE keyword specified but no change number given
Cause:	The CHANGE keyword was specified on the command line, but no change number was given.
Action:	Retry the command using a valid change number after the CHANGE keyword.

ORA-00275:	media recovery has already been started
Cause:	An attempt was made to start a second media recovery operation in the same session.
Action:	Complete or cancel the first media recovery session or start another session to perform media recovery.