How to convert Mesh to a smooth Polysurface

I have created triangulated mesh from RV2, and I want to make it into one smooth surface. What would you suggest me to do?

What Rhino version is this file created in?

Testing 3dm Archive: C:\Users\martinsiegrist\Downloads\mesh_surface.3dm
Start Section: 457 bytes (offset 0 to 457)
Offset: 0
3dm archive version: 70
Interface Name: Rhinoceros 7.1 - tion, build 2020-12-08 - (compiled Dec 8 2020)
SDK Version: 2348836105.2382657549
OpenNURBS Version: 2382657549
3dm Version: 7
Operating System: Windows 10.0.19044 SR0.0 or greater, 64-bit, platform 2, version 10.0 build 19044 sp 0.0, suite 768, product type 1
Runtime: ON::RuntimeEnvironment::Windows 3DM I/O processor: OpenNURBS toolkit version 2382657549 (compiled on Dec 8 2020)

Properties Section: 49238 bytes (offset 457 to 49695)
3dm archive openNURBS version: 2382657549 (7.1 2020-12-08:1)
Application Information:
Name: “Rhinoceros 7”
URL: “http://www.rhino3d.com
Details: “tion, build 2020-12-08”
Revision History:
Create Time: Monday April 25 12:11:42 2022 UCT
Last Edit Time: Monday April 25 12:11:42 2022 UCT

Interesting… The file has been deleted… :face_with_monocle: