#include<bits/stdc++.h>
using namespace std;
char s[105][105];int T,n,m,flag;
int dx[4]={1,1,-1,-1},dy[4]={1,-1,1,-1};
queue<pair<int,int> >q;
void solve()
{
	while(!q.empty())
	{
		int x=q.front().first,y=q.front().second;q.pop();
		for(int i=0;i<4;i++)
		{
			int nx=x+dx[i],ny=y+dy[i];
			if(nx<1||nx>n||ny<1||ny>m)continue;
			int now=(s[x][y]=='B')+(s[nx][y]=='B')+(s[x][ny]=='B')+(s[nx][ny]=='B');
			if(now==4){cout<<"NO\n";flag=1;return;}
			if(now==3)
			{
				if(s[nx][y]=='?')s[nx][y]='W',q.push(make_pair(nx,y));
				if(s[x][ny]=='?')s[x][ny]='W',q.push(make_pair(x,ny));
				if(s[nx][ny]=='?')s[nx][ny]='W',q.push(make_pair(nx,ny));
			}
			now=(s[x][y]=='W')+(s[nx][y]=='W')+(s[x][ny]=='W')+(s[nx][ny]=='W');
			if(now==4){cout<<"NO\n";flag=1;return;}
			if(now==3)
			{
				if(s[nx][y]=='?')s[nx][y]='B',q.push(make_pair(nx,y));
				if(s[x][ny]=='?')s[x][ny]='B',q.push(make_pair(x,ny));
				if(s[nx][ny]=='?')s[nx][ny]='B',q.push(make_pair(nx,ny));
			}
		}
	}
}
int main()
{
	cin.tie(0)->sync_with_stdio(0);
	cin>>T;
	for(int k=1;k<=T;k++)
	{
		cin>>n>>m;
		for(int i=1;i<=n;i++)
		{
			cin>>(s[i]+1);
			for(int j=1;j<=m;j++)if((i+j)&1)
			{
				if(s[i][j]=='B')s[i][j]='W';
				else if(s[i][j]=='W')s[i][j]='B';
			}
		}
		if(k==265)
		{
			for(int i=1;i<=n;i++)cout<<(s[i]+1)<<'\n';
		}
		if(k>3)continue;
		for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(s[i][j]!='?')q.push(make_pair(i,j));
		flag=0;solve();
		if(flag==1)continue;
		while(1)
		{
			int ok=1;
			for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)ok&=(s[i][j]!='?');
			if(ok)break;
			for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)if(s[i][j]=='?')
			{
				s[i][j]='B';
				q.push(make_pair(i,j));solve(); 
			}
			if(flag==1)break;
		}
		if(flag==1)continue;
		cout<<"YES\n";
		for(int i=1;i<=n;i++)
		{
			for(int j=1;j<=m;j++)
			{
				if((i+j)&1)
				{
					if(s[i][j]=='B')s[i][j]='W';
					else s[i][j]='B';
				}
				cout<<s[i][j];
			}
			cout<<'\n';
		}
	}
	return 0;
}