Transfer name to the new property title and remove the same name from existing property title

I bought 3 bedroom house with my sister-in-law and we built a 1 bedroom house on the same land so at a moment both properties under the same property title. Currently I live in 1 bedroom house and my sister-in-law lives in 3 bedroom house. Now we would like to separate two houses and land, and create new property title for 1 bedroom house, I will be only the owner of 1 bedroom house and my sister-in-law will be only the owner of 3 bedroom house. I understand we need to fill form TP1, application form AP1 and ID1(or ID3) to transfer my name to new 1 bedroom property title and than fill the form TR1, AP1, ID1(or ID3) to remove my name from existing 3 bedroom property title. Can I fill all these forms in the same time and send it to the Land Registry? I can pay for submitting 2 applications. The mortgage paid and we know about tax implications. Please give us advise how to transfer my name to new property title and remove my name from existing property title.

Oleksandr - you can do both transactions and submit them together as you state and pay the registration fees as a single payment as well if you wish to. Just make it clear on submission that the fee is for both and that they are linked https://www.gov.uk/registering-land-or-property-with-land-registry/transfer-ownership-of-your-property

Thank you Adam for your answer. Can I use only one ID form for both transactions?

Oleksandr - you may and again ensure you include a note to cross refer on both applications re the identity form(s) as appropriate

Thank you Adam. How long normally it takes for Land Registry to make decision on this type of application? Do I have to send tax calculations and proof of Capital Gain Tax or Stamp Duty Land Tax payment to Land Registry?

Oleksandr - wait times are lengthy so you should expect to wait 12+ months before processing starts. You'll need to consider SDLT as part of the process and lodge the appropriate evidence once obtained from HMRC as appropriate. It's HMRC that are concerned with CGT and we don't need those details