We would like to convert from Tabular model to Multi dimensional model .Please let me know the action items to be considered in the implementation.

You can not convert Tabular model to Multidimensional model or vice versa. 

The only way is to redesign Multi-dimensional model. Sad but true !

• Proposed as answer by Tom Phillips 14 hours 19 minutes ago
• Edited by Anuj Tripathi 14 hours 19 minutes ago spelling mistake

Hi Srivats,

Analysis Services provides two distinct approaches for data modeling: tabular and multidimensional. While there is significant overlap between them, there are also important differences between them. Which you can see on the links below.
https://msdn.microsoft.com/en-us/library/hh212940.aspx?f=255&MSPPError=-2147217396
http://www.egroup-us.com/2014/07/tabular-vs-multidimensional/

Currently, there is no such a tool to convert Tabular model to Multidimensional model. You can redesign Multi-dimensional model. The links below are for you reference.
http://www.codeproject.com/Articles/658912/Create-First-OLAP-Cube-in-SQL-Server-Analysis-Serv
http://www.codeproject.com/Articles/607134/BuildingplusYourplusFirstplusAnalysisplusServicesp

Thank you for your understanding.

Regards,