What credentials i should use to downgrade to cd6 6.3.1?

[#1]

Hello

I start upgrade to 7.1.4 and cant start it in case of incomplete tasks

is any way to downgrade to 6.3.1?

[#2]

Unless your upgrade is finalized you can roll back 

https://docs.cloudera.com/documentation/enterprise/upgrade/topics/ug_cdh_upgrade.html#concept_cfj_td...

https://docs.cloudera.com/documentation/enterprise/upgrade/topics/install_rollback.html#concept_sfz_...