The success of conversion from VBS to VBA would depend on the commands users have used in the VBS code. Because VBA is a subset of VBS it would convert (more easily) if only VBS commands were used that exist in VBA. There are many dedicated posts from Visual Basic programmers on the net about converting VBA to VBS.
Convert Visual Basic script to Visual Basic VBA module.
We found one software available in the database for this conversion.
Microsoft Windows software - convert vbs to vba on Windows
A programming language and integrated development environment for Microsoft Windows
Convert from vbs file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.