Upgrade SLES in HA from 12.5 to 15.X (SAP HANA usage)


we would like to upgrade our SuSE 12.5 two-nodes cluster to SuSE 15.5 (or any more recent release).
This cluster is used as SAP HANA database server and it was already upgraded from 12.3, 12.4 and 12.5 in the past. The cluster runs very well and we prefer to leave it as is.
Now SAP HANA is already upgraded to 2.0 SPS06 patch 7 so it can support 12.5 and 15.X release.

Where can I find a procedure and/or documentation to upgrade?

Thank you for you support.