There is no compliance required to be done to convert the residential land into commercial land.

Only after the making the constructions the building requires separate license/permission t use this as commercial property like trade license. 

If you give further details of the query then I can advise further.

Contact the local property tax authorities in your local body/municipal office and request them to convert it to residential to commercial. They will do it by revising the property tax. The tarrif for commercial is two times comparing residential.

Land conversion is a process of converting agricultural land for non-agricultural purposes. Agricultural lands cannot be utilised for the development purposes such as residential, commercial, industrial, or medical facilities besides on conversion of the land into non-agricultural lands. As per the provisions contained in Tamil Nadu Change of Land Use (From Agriculture to Non-agriculture Purposes in Non-planning Areas) Rules, 2017, agriculture land in the state cannot be used for the development purpose, without the permission of the prescribed authority. 

Tamil Nadu Change of Land Use Rules

As described above, Tamil Nadu Change of Land Use (From Agriculture to Non-agriculture Purposes in Non-planning Areas) Rules, 2017 moderates the process of changing land use from agriculture land to non-agriculture purpose in Tamil Nadu. The process of conversion of land will be completed on payment of a premium, and on verification, if it is found that the owner of the land fulfils all the conditions a conversion order will be granted to the landholder.

 This TN land use rule applies to all areas in the State of Tamilnadu, except those notified as planning areas by state Government.

Exempted Lands for Tamil Nadu Land Conversion

As per Tamil Nadu Land usage change rules, no permission will be granted if the proposed conversion is any of the following types of lands:

• Public water body like channel, tank, canal, lake, river,
• Government Pocomoke land, temple lands, wakf properties and other lands belonging to religious/charitable institutions.
• Vacant lands with any encroachment on a street road or public road or on any other land over which the owner does not possess ownership rights
• Properties below the alignment of high tension and extra high voltage electric line including tower lines
• Land which is fit for the cultivation

Prescribed Authority for Land Conversion

Land can be called non-agricultural land if any activity like development is carried over on the agriculture land which makes agriculture land unfit for cultivation.

As per the Tamil Nadu Land use change rules, before carrying out any development on the agriculture land, an eligible person need to apply to the local authority for the permission to convert the use of agricultural land into the non-agricultural purpose.

Applicable fee for Tamil Nadu Land Conversion

The applicant will have to pay a non-refundable scrutiny fee of Rs.1000 per plot to the local authority.

Tamil Nadu Land Conversion Charge

Tamil Nadu land use conversion charge at the rate of 3% of the market value fixed under the Indian Stamp Act, 1899 need to be paid to the local authority, and the concerned body will deposit the amount in Government head of account and grant permission for carrying out the development works.

Document Required 

For obtaining completing Tamil Nadu land conversion, the applicant has to attach documents as mentioned below:

• Copy of sale deed, lease deed and power of attorney self-attested by the applicant
• Certificate of ownership should be obtained from the Executive Officer, Town Panchayat or Commissioner, Municipality Corporation in case of urban local bodies
• In the case of rural local authorities, certificate of ownership to be obtained from the Block Development Officer (BDO) of Block Panchayat, Village Panchayat
• FMB or Town Survey sketch
• 
  Patta, Chitta or Town Survey Land Records (TSLR) in owner’s name
• Site plan inappropriate scale of 1:400/800/1600
• Proposed layout for sub-division plan (In case of layout/subdivision proposal)
• To plan to show all existing developments surrounding the site for 500-metre radius
• 
  Encumbrance certificate for 13 years issued not before 30 days from the date of submitting the application
• If the proposed land lies within a distance of thirty meters from Railway property boundary and the applicant proposes to have the plot for building within the area then-No Objection Certificate (NOC) from Railways

You can approach the municipal department of the Ooty, you have to pay the conversion charges and pay property tax accordingly for the commercial property after conversion.

You have to make application to muncipal corporation for conversion of residential property into commercial property 

2) it should not take more than 6 months 

Dear Sir,

Tamil Nadu Change of Land Use (From Agriculture to Non-agriculture Purposes in Non-planning Areas) Rules, 2017 moderates the process of changing land use from agriculture land to non-agriculture purpose in Tamil Nadu. The process of conversion of land will be completed on payment of a premium, and on verification, if it is found that the owner of the land fulfils all the conditions a conversion order will be granted to the landholder.

1.  Conversion from Residential to Commercial is possible, BUT with proper NOC from Society /Association and applying for permission from the local Civic authority /collector office.

2. The above must be done thru a registered Architect, by following due procedure of law.

In case your state allows this, it is necessary to get an approval from the housing society before conversion of residential property to commercial property. ... Once a property is marked as commercial property, it would be treated as a commercial property for all purposes, which includes paying more as property.

Under Notifications under Tamil Nadu Town and Country Planning Act.
Variation to the Master Plan for Erode Local Planning Area;

Regulation for Special building. - (1) “Special buildings” means -
(a) a residential or commercial buildings with more than two floors; or
(b) a residential building with more than four dwelling units; or
(c) a commercial building exceeding a floor area of 300 square metre:
Provided that any construction in the second floor with prior permission as an addition to an existing ground and first storeyed
authorised ordinary residential building which is three years old shall not be construed as a “Special Building”.

You may approach town and country planning department for completing the legal formalities in this regard if you want to convert the same legally.